Showing papers in "International Review of Mechanical Engineering-IREME in 2013"
TL;DR: In this paper, the authors presented an original method to determine the efficiency of a mechanism with cam and follower, which consists in eliminating the friction modulus and optimizing the distribution mechanism.
Abstract: The paper presents an original method to determine the efficiency of a mechanism with cam and follower. The originality of this method consists in eliminating the friction modulus. In this research it analyses four types of cam mechanisms: 1.The mechanism with rotary cam and plate translated follower; 2.The mechanism with rotary cam and translated follower with roll; 3.The mechanism with rotary cam and rocking-follower with roll; 4.The mechanism with rotary cam and plate rocking-follower. For every kind of cam and follower mechanism one uses a different method to determine the most efficient design. We take into account the cam’s mechanism (distribution mechanism), which is the second mechanism in internal-combustion engines. The optimizing of this mechanism (the distribution mechanism), can improve the functionality of the engine and may increase the comfort of the vehicle too.
50 citations
TL;DR: In this paper, the authors presented an original method to increase the efficiency of a mechanism with cam and follower, which can be used to improve the yield of the internal heat engines.
Abstract: The paper presents an original method to increase the efficiency of a mechanism with cam and follower. The distribution mechanisms work with small efficiency for about 150 years; this fact affects the total yield of the internal heat engines. Much of the mechanical energy of an engine is lost through the mechanism of distribution. Multi-years the yield of the distribution mechanisms was only 4-8%. In the past 20 years it has managed a lift up to the value of 14-18%; car pollution has decreased and people have better breathing again. Meanwhile the number of vehicles has tripled and the pollution increased again. Now, it’s the time when we must try again to rise the yield of the distribution mechanisms. This paper treats only two modules: the mechanism with rotary cam and plate translated follower and the mechanism with rotary cam and translated follower with roll.
36 citations
TL;DR: In this paper, the authors reviewed the various production techniques, properties of vegetable oil and its biodiesel along with the challenges faced and experiments carried out by various researchers around the world.
Abstract: The rising energy needs resulting from increased claim and diminishing supply, alternative energy sources are receiving more attention. In addition, the increasing global concern has caused to focus on the oxygenated diesel fuels because of the environmental pollution from internal combustion engines. Vegetable oils possess almost the same heat values as that of diesel fuel with inherently high viscosity. Vegetable oil is easily available, renewable fuel with short carbon cycle period and is environment friendly. These are the triggering factors for research all over the world to consider vegetable oils and their derivatives as alternative to petroleum diesel. Researchers experimented that vegetable oil fuelled engine power output and fuel consumption are comparable to diesel when fuelled with vegetable oil and its blends and produce less carbon monoxide (CO), unburned hydrocarbon (HC), and particulate emissions compared to mineral diesel fuel but higher NOx emissions than that of pure diesel fuel. This paper reviews the various production techniques, properties of vegetable oil and its biodiesel along with the challenges faced and experiments carried out by various researchers around the world.
21 citations
TL;DR: The results showed that the anti-friction and anti-wear ability of PFAD were higher than those of Engine and Hydraulic mineral oils as mentioned in this paper, however, the amount of viscosity oil for PFAD was less than Engine oil.
Abstract: Lubricant oils have an important role in manufacturing processes for reducing friction and wear between in-contact rotational pieces with different speeds. Vegetable oils are known as new, clean and renewable sources. Palm Fatty Acid distillate (PFAD) is sourced from the vegetable oil family and is potential as an alternative source of mineral lubricant/Hydraulic oils. This study was performed utilizing various speeds (800, 1000, 1200, 1400 and 1600rpm) and according to the American Society for Testing and Materials (ASTM) with number D 4172 (speed 1200 rpm, load 392N, temperature 75°C and in one hour) using a four ball wear machine tester. To evaluate the PFAD results, similar experiments were done using Engine and Hydraulic oil and the results were compared mutually. The results showed that, the anti-friction and anti -wear ability of PFAD were higher than those of Engine and Hydraulic mineral oils. Also, the value of flash temperature parameter of PFAD oil was higher than other test oils. However, the amount of viscosity oil for PFAD was less than Engine oil.
18 citations
TL;DR: In this article, numerical studies of turbulent heat transfer in separation flow were presented, where the authors investigated the effect of expansion ratio, Reynolds number, step height, ribs and twist angle on improvement of heat transfer.
Abstract: The numerical studies of turbulent heat transfer in separation flow presented in this paper. Enhancement of heat transfer rate in turbulent separation flow at sudden expansion in passage, over forward or backward facing-steps, blunt body, ribs channel, and swirl generators in channels were investigated numerically. Different models (CFD) used to study heat transfer characteristics and fluid flow in separation and reattachment region and compared results with previous experimental data. The effect of expansion ratio, Reynolds number, step height, (shape, number, and angle) of ribs and (length, twist angle, and gap width) twist the tape on improvement of heat transfer were referred. The numerical results indicated increases of heat transfer coefficients with increases in the above parameters. The numerical simulations derived from finite volume, element, and difference methods for evaluation of turbulent heat transfer in separated flow and employed several computational programs.
16 citations
TL;DR: In this article, the effect of various ratios of Na2SiO3/NaOH ratio, kaolin/alkaline activator ratio and sand/kaolin ratio to the strength of clay-based geopolymer brick was studied.
Abstract: The strength of geopolymer depends on the nature of source materials. For example, geopolymer produced with calcined source material such as calcined kaolin, fly ash, ground granulated blastfurnace slag (GGBS) and others produce a higher compressive strength compared to geopolymer produced with non-calcined source material such as kaolin. This paper studied the effect of various ratios of Na2SiO3/NaOH ratio, kaolin/alkaline activator ratio and sand/kaolin ratio to the strength of clay - based geopolymer brick. The samples had been tested to determine their compressive strength, density, and water absorption properties. Compression tests were conducted at seventh day of testing of all specimens. Tests were carried out on standard size of geopolymer brick according to British Standard (BS 3921).
15 citations
TL;DR: In this article, a methodology for identifying and analysing the performance of an I.C. engine and the reconstruction of the morpho-dynamical vibration of the engine is presented.
Abstract: The aim of this paper is to illustrate a methodology for identifying and analysing the performance of an I.C. engine and, at the same time, for the reconstruction of the morpho-dynamical vibration. Some technical considerations and a real application explain the method by completing the description of the phenomena observed. It allows to focus a methodology which should concur to the improvement of the diagnostics of anomalies useful for determining the correct operating process of an I.C. engine.
15 citations
TL;DR: In this article, an analytical approach is proposed in combination of frequency analysis and time domain simulation to predict harvested resonant power and energy harvesting efficiencies of mechanical systems with built-in piezoelectric material.
Abstract: Conversion of vibration energy in a structure, machine or vehicle into electric energy will improve reliability, comfort and energy utilisation efficiency, and can potentially reduce the amplitude of vibration and associated damaging effects An analytical approach is proposed in combination of frequency analysis and time domain simulation The main advantage of the approach is its capability to predict harvested resonant power and energy harvesting efficiencies of mechanical systems with built-in piezoelectric material, from a resonant frequency, mechanical damping, external load resistance and piezoelectric material properties regardless of the system size The approach allows for prediction of output voltage and harvested resonant power from measured field vibration acceleration data It allows for a parameter study and optimization of piezoelectric vibration energy harvesters The dimensionless harvested resonant power and energy harvesting efficiency formula developed from this paper are useful for performance evaluation of the vibration energy harvesters ranging from macro to micro scales, even to nano scales Potential industrial applications would be in ambient vibration energy harvesting analysis for machines or structure systems with built-in piezoelectric material These systems may include engine torsion vibration absorbers (engine harmonic balancer), vehicle chassis suspension/mounting systems, vehicle power-train suspension/mounting systems, wheels and tyres or vehicle body panels The harvested electric energy is expected to be used to power electronic devices, self-sustaining micro- and nano-scale sensors, or remote sensing systems including automotive electronics, sensors or wireless sensor nodes
15 citations
TL;DR: In this article, an experimental study was conducted to identify the common engine part load conditions between Malaysian city driving and NEDC (New European Driving Cycle) test on a 4 cylinder gasoline fuelled engine, with multi-point fuel injection system, and continuous variable transmission vehicle.
Abstract: This paper describes an experimental study conducted to identify the common engine part load conditions between Malaysian city driving and NEDC (New European Driving Cycle) test on a 4 cylinder gasoline fuelled engine, with multi-point fuel injection system, and continuous variable transmission vehicle. This is to pinpoint a regional area from the part load map in the attempt to strategize key technologies such as CDA (Cylinder Deactivation) or CNG (Compressed Natural Gas). Technologies such as CDA or CNG do not operate at all engine operations. Due to certain drawbacks, the operation of the technologies must be strategized to obtain most benefit from the engine. With the knowledge of the common part load region, these technologies could be integrated and strategized into the region to reduce overall fuel consumption. With improvements in fuel consumption respective to the identified common part load operations, the overall fuel consumption benefit does not only serve the legislation but also most importantly benefit the local consumers who travel on Malaysian roads.
14 citations
TL;DR: In this paper, a numerical approach carried out using an industrial code CFD Fluent 6.2.13 based on the finite volumes method discretization of Navier-Stokes equations formulated in variables (U.V.P).
Abstract: In this work, we study the case of highly viscous fluids in a classical system of agitation: a cylindrical tank with plate bottom without obstacles agitated by a gate impeller agitator. We devote to a numerical approach carried out using an industrial code CFD Fluent 6.2.13 based on the finite volumes method discretization of Navier - Stokes equations formulated in variables (U.V.P). The threshold of flow related to the viscoplastic behaviour is modelled by a theoretical law of Bingham. Heat transfer to Bingham plastic fluids in an agitated vessel .It is a commonly used in chemical and food industry processes. However, little is known about the effects of mixing system geometry and the influence of rheological properties of the liquids on the heat transfer phenomenon. The hydrodynamic and thermal behaviours induced by gate agitator. Heat transfer is applied on the jacketed wall of the stirred vessel. Solutions of the time-averaged Navier–Stokes and energy equations are developed using a control volume discretization method. Streamlines and isotherm represent the corresponding flow, field and the global distributions of Nusselt number are also presented.
13 citations
TL;DR: In this article, the results of experimental tests direct to investigate the handlebar dynamic response is reported; the investigation is adopted to evaluate the possibility of adopting a vibration exciter placed in correspondence of the grips that could provide an alarm signal when a danger situation occur.
Abstract: Motorcycle driver interacts with the vehicle through the hands, feet and buttocks. Through these parts of the body, the driver perceives vibrations due to engine and road roughness. A good level of comfort would require that handlebar and foot pegs natural frequencies should not line up with the operating range frequencies. In this paper the results of experimental tests direct to investigate the handlebar dynamic response is reported; the investigation is adopted to evaluate the possibility of adopting a vibration exciter placed in correspondence of the grips that could provide an alarm signal when a danger situation occur. This type of active assistance has already been used for cars and has proved effective in the accidents prevention.
TL;DR: In this article, an experimental test rig aimed to characterize mechanical properties of a pneumatic tire, together with some results, is presented, in particular: the normal interaction characteristic, the radial stiffness, the total stiffness and the longitudinal hysteretic cycles.
Abstract: In this paper an experimental test rig aimed to characterize mechanical properties of a pneumatic tyre, together with some results, is presented. The objective is to determine tyre mechanical characteristics useful to physically model its behaviour; in particular: the normal interaction characteristic, the radial stiffness, the total stiffness and the longitudinal hysteretic cycles. To this aim two different kind of tests have been executed: radial and longitudinal. In the radial test the load is statically applied to the tyre, along the vertical direction, by means of an hydraulic press and it is measured together with the consequent radial deformation, so allowing the estimation of the tyre normal interaction characteristic and of its radial stiffness. Different radial tests can be conducted for an assigned tyre varying the inflation pressure. The longitudinal tests are conducted applying, under an assigned constant vertical load, a variable horizontal strain to the tyre by means of a linear actuator, two profile rail guides and a system to transfer the horizontal motion to the contact patch of the tyre, opportunely placed on a moving steel plate placed on the two linear guide rails. During the tests the horizontal load and the resulting deformations are measured and acquired so allowing the estimation of tyre total stiffness and of its longitudinal hysteretic cycles. Longitudinal tests can be conducted varying the assigned vertical load, the horizontal displacement law in terms of frequency and amplitude, the tyre inflation pressure. All the different types of rim can be mounted on the test rig thanks to a universal quick flange.
TL;DR: In this paper, a simulation model was developed to investigate engine performance based on computational simulations and an experiment investigation was conducted based on ISO 3046, the experiment has been using eddy current dynamometer engine test bed.
Abstract: This research methodology has been explained step-by-step and in detail for the simulation and experimental investigation of compressed natural gas engine performance. The engine simulation model was developed to investigate engine performance based on computational simulations. The engine computational simulation model has been using one dimensional model. The experiment investigation was conducted based on ISO 3046. The experiment has been using eddy current dynamometer engine test bed. The simulation and experiment was performed to investigate engine performance parameters such as intake pressure and temperature, cylinder pressure and temperature, torque, power, break mean effective power, specific fuel consumption and exhaust pressure and temperature.
TL;DR: In this article, the effects of using polymer oil obtained from the plastic waste as a fuel in diesel engine were investigated. And the experimental result showed that the carbon monoxide, carbondioxide, Oxides of nitrogen and smoke were significantly reduced.
Abstract: This paper describes an experimental study of using polymer oil obtained from the plastic waste as a fuel in diesel engine. In this study, the effects of using polymer oil – ethanol fuel blends [PE10, PE20] on the engine performance, exhaust emissions and combustion characteristics have been experimentally investigated. In the present work, 10% ethanol and 90% polymer oil, called here as PE10 and 20% Ethanol and 80% polymer oil called here as PE20 were used in a single cylinder four stroke, water cooled diesel engine. The engine fuelled by the blends is comparable with that fuelled by diesel. The experimental result showed that the carbon monoxide, carbondioxide, Oxides of nitrogen and smoke were significantly reduced. Unburned hydrocarbon, brake specific fuel consumption and brake thermal efficiency were found to have increased with ethanol-polymer oil blends.
TL;DR: In this article, a test rig to evaluate the possibility of performing a dynamic characterization of the out-of-plane modes instead of road tests, was developed, which allows tests to be extended to low and very high speeds and assures test repeatability.
Abstract: Knowledge of “out of plane” modes is very important when defining the dynamic behavior of a motorcycle and its stability and handling in particular. Several mathematical models are available in the literature to study and preview frequency, damping and stability of these modes but, in order to verify these values, road tests must be performed which are sometimes dangerous for the tester. A test rig to evaluate the possibility of performing a dynamic characterization of the out of plane modes instead of road tests, was developed. The use of a test rig is certainly limited compared with road tests since the physical phenomena are not completely reproduced but allows tests to be extended to low and very high speeds and assures test repeatability. This paper presents the test rig and the results of an experimental investigation conducted on a scooter; the tests were conducted in steer free control condition with different inertia and tire characteristics.
TL;DR: In this article, a technique called exhaust gas recirculation (EGR) was used to crack the harmful NOX component of the diesel emissions, which is a potential cause for smog and acid rain.
Abstract: In the wake of current energy scenario, major research is focused on sustainable energy solution with major emphasis on energy efficiency and use of renewable energy sources. Diesel engines have proven their utility in the transportation and power sectors due to their higher efficiency and ruggedness. Depending upon the availability and production capabilities, biodiesel is derived from a large variety of oilseed. Sterculia bio fuel is identified and proved to be the best alternative to the diesel engine. Laboratory tests were carried out to determine the properties like specific gravity, kinematic viscosity, cloud point, pour point, flash point, fire point and calorific value of the fuels used. The overall performance and emission tests have given good results except for the NOX component of the emission, which is a potential cause for smog and acid rain. This paper also focuses on the reduction of this component to a great extent with the implementation of a technique called Exhaust Gas Recirculation. In this method the water cooled exhaust of the engine is circulated back to the inlet manifold to crack the harmful NOX. This makes the bio diesel a completely emission free alternative.
TL;DR: In this paper, a dual fuel blend with pure diesel in a single cylinder direct injection constant speed diesel engine was analyzed by varying the power outputs with different proportions of the fuel blends.
Abstract: In the fast growing world of automobiles, the demand for petroleum products is increasing day by day. Many of renewable energies are used to full fill that demand. One of the best alternatives is the use of biodiesel. In this study a dual fuel blend with pure diesel in a single cylinder direct injection constant speed diesel engine was analyzed by varying the power outputs with different proportions of the fuel blends. In the dual fuel operation, the rubber seed oil and jatropha oil blends with diesel. The proportions of 20% and 40% blend have been investigated on volume basis. In this dual fuel operation is observed that they have higher emission of hydrocarbon (HC) and carbon monoxide (CO) emissions than the ester, diesel blend. The ignition delay was reduced using dual fuel blend with diesel and efficiencies were improved. The proportion, B20 (20% of biodiesel) is gives the optimum efficiency with low emission.
TL;DR: In this paper, continuous and discrete phases have been coupled in order to predict convective heat transfer between solid and fluid within packed beds, and the obtained results show high correspondence, and therefore, it is believed that the proposed numerical approach is well suitable to treat challenging granular applications.
Abstract: Packed bed reactors dominate a broad range of engineering applications. In a packed bed reactor, heat is transferred from the solid particles to the gas flow stream through the void space between particles. Using a XDEM approach, continuous and discrete phases have been coupled in order to predict convective heat transfer between solid and fluid within packed beds. For the solid matrix a discrete intra-particle model, namely DPM, was used to solve for each particle of the bed, and a CFD tool was employed to resolve the fluid flow. Analytical solutions, as well as experimental and other authors’ simulation data were employed in different, ordered and non-ordered, particle arrangements. The obtained results show high correspondence, and therefore, it is believed that the proposed numerical approach is well suitable to treat challenging granular applications.
TL;DR: In this paper, a low cost electronic fuel injection (EFI) system developed for a small two-stroke SI engine was used to reduce emissions and enhance engine performance by providing appropriate amount of fuel quantity at all operating conditions of engine.
Abstract: Fuel prices are increasing continuously all over the world. Also, globally the vehicle density is increasing according to geometric progression which contributes as a major source of air pollution. Therefore, improvement is continuously demanded in design of an efficient engine producing less harmful emissions. Many researcher and engine manufacturers in this field are optimistic and enthusiastically working to achieve these objectives. This work mainly focuses on low cost electronic fuel injection (EFI) system developed for a small two stroke SI engine. Engine mapping plays vital role to reduce emissions and enhance engine performance by providing appropriate amount of fuel quantity at all operating conditions of engine which results in complete combustion. This paper presents the experimental work using engine mapping process with EFI system, graphical user interface based software – Proteous and modified fuel injection system. The experimental results of carburetor mode and EFI mode are included and compared.
TL;DR: In this article, a CFD approach using CONVERGE CFD Code was applied on a direct injection spark ignition engine at low regime and lean mixtures, where three hydrogen fractions were considered 0, 10% and 18%.
Abstract: This paper deals with the subject of natural gas-Hydrogen blends as alternative fuel for spark ignition engine. First, a brief overview on previous works in this field was presented. Then, a numerical investigation focusedon the effect of hydrogen addition on the performances and emissions was also presented. A CFD approach using CONVERGE CFD Code was applied on a direct injection spark ignition engine at low regime and lean mixtures. A detailed chemistry associated with AMR (Adaptive Mesh Refinement) technique was adopted. To illustrate the effect of hydrogen addition to natural gas, three hydrogen fractions are considered 0%, 10% and 18%. The obtained results showthatthe promotion of the chemical reaction with hydrogen addition is mainly due to the increase of free radicals H, O, OH in the flame as a result of hydrogen addition. Hence, the heat release rate starting is advanced with the increase of hydrogen fraction while the combustion duration decreases. It is observed that the heat release rate and the maximum in cylinder temperature increase when hydrogen is added. Exhaust CO emissions decreases with the increase of hydrogen fraction, while NOx emissions increase. Hydrogen addition could give a great potential to reduce soot formation.
TL;DR: In this paper, the authors give an overview about performance and emission of the combustion improving diesel fuel additives. But, their focus was on the use of additive treated fuel to improve the performance, reduce emissions and give longer life of the engine.
Abstract: Diesel engines are widely used for transportation and power generation due to its better performance, reliability and durability. For the past three decades, there has been a consistent worldwide demand for the diesel fuel and quality, which resulted in degraded engine performance and increased pollutant concentration. At present demand for better diesel fuel is more. Diesel fuel quality can be improved either by better processing or with the use of additives. Additive treated fuel contributes to improve the performance, reduce emissions and gives longer life of the engine. Detergents and dispersant, cleanliness additive, cetane improver, combustion modifier and multifunctional additives are the major groups of additives. Detergent additives effectively prevent the buildup deposits, while dispersant include cleaning and disperse particulate matter in an extremely fine state. Cleanliness additives are organic detergents, to prevent deposits formation in the fuel injection system and maintain the injection system cleanliness over the useful life of the engine. Cetane improvers control the ignitability of diesel fuel, when it is sprayed into the combustion chamber and reduce the ignition delay period for the fuel. Combustion modifier is a group of metallic or ash containing additive, which is added in the fuel with a level of parts per million. The objective of the present paper is to give an overview about performance and emission of the combustion improving diesel fuel additives.
TL;DR: In this article, the compressive strength and water absorption of fly ash-based geopolymer bricks were investigated which are produced by applying heat treatments between the ranges of room temperature to 80°C at several period of time for curing (1 - 24) hours.
Abstract: The influence of curing time and curing temperature on properties of fly ash-based geopolymer bricks has been studied. The compressive strength and water absorption of geopolymer bricks were investigated which are produced by applying heat treatments between the ranges of room temperature to 80°C at several period of time for curing (1 – 24) hours. In this research, the fly ash-based geopolymer bricks showed that the curing system have a significant effect to the properties of fly ash-based geopolymer bricks. It was observed that prolonged curing time en-hanced the geopolymerization reaction resulting increase in compressive strength. The highest compressive strength of geopolymer bricks for different curing temperature given by bricks sample cured at 70°C for 24 hours at the ageing of 7 days.
TL;DR: In this article, the effect of various parameters on multi-performance characteristics in turning of Al-SiC-Gr metal matrix composites was investigated, and the confirmation experiment revealed that the selected optimal combination of process parameters is able to achieve desired performance characteristics.
Abstract: The utilization of metal matrix composite materials are increased enormously in many engineering fields because of many beneficial properties. Consequently, the need for precise machining of composites has also been improved. In this present study, efforts are made to investigate the effect of various parameters on multi-performance characteristics in turning of Al-SiC-Gr metal matrix composites. Taguchi design method was used to conduct experiments. The influence of cutting speed, feed rate, depth of cut and combined equal weight fraction of SiC-Gr on the response variable of surface finish, material removal rate of the work piece and flank wear of the tool are established. The significance of the parameters and its optimum level is determined for each individual response by using analysis of variance (ANOVA). The optimum machining parameters for multi-performance characteristics are also obtained by weighted grey relational approach. The confirmation experiment revealed that the selected optimal combination of process parameters is able to achieve desired performance characteristics.
TL;DR: In this article, a semi-active differential called MRF LSD (MagnetoRheological Fluid Limited Slip Differential) is presented that allows to bias torque between the driving wheels.
Abstract: This paper presents a semi-active differential, called MRF LSD (MagnetoRheological Fluid Limited Slip Differential) that allows to bias torque between the driving wheels. It is based on the magnetorheological (MR) fluid employment, that allows to change, in a controlled manner, the differential locking torque and, consequently, the torque bias ratio. The device is an adaptive one and allows to obtain an asymmetric torque distribution in order to improve vehicle handling. The device modelling and the control algorithm, realized for this activity, are described. The illustrated results highlight the advantages that are attainable regarding directional behaviour, stability and traction for a front wheel drive (FWD) vehicle. A comparison with a traditional passive limited slip differential has been conducted.
TL;DR: In this article, the performance and emission characteristics of a variable compression ratio diesel engine with sardine oil ethyl ester were investigated at different compression ratios of 16.0, 17.5 and 19.0.
Abstract: This study investigates the performance and emission characteristics of a variable compression ratio diesel engine which is fuelled with sardine oil ethyl ester. A single cylinder four stroke diesel engine was used for the experiments at various load and speed of 1500 rpm. In order to find out optimum compression ratio experiments were carried out on a single cylinder four stroke variable compression ratio diesel engine. Tests were carried out at compression ratios of 16.0, 17.5 and 19.0. Results showed a significant improved performance and emission characteristics at a compression ratio 16.0. It has been observed that there is an increase in Break thermal efficiency, Exhaust gas temperature and Carbon monoxide for compression ratio 16, Hydro carbon and Nitric oxide is lower for compression ratio 16.
TL;DR: In this article, the Abrasive Water Jet Machining (AWJM) process is investigated from different point of view and concluded a number of remarks regarding the different aspect of the process.
Abstract: As technology advances, understanding the mechanism behind hybrid nontraditional processes is prerequisite for its effective commercial application. To enhance the versatility of Abrasive water jet machining (AWJM) process a comprehensive study of previous work is necessary. Researchers investigated the AWJM process from different point of view and concluded a number of remarks regarding the different aspect of the process. Widely scattered technical information are collated and explicitly presented in this paper. Findings from different works are broadly classified in modeling, parametric study and optimization. As one main benefit of using AWJM is that it is capable to machine almost all types of materials, so materials used for experimental works are also highlighted. A number of possible future scopes in this field of study are added in conclusion of this paper.
TL;DR: In this paper, a spray behaviour based on digitalised images is presented for a specific fluid the working range of a spray, the main parameters indicating the spray performances, e.g., cone angle, supply pressure and mass flow rate are defined.
Abstract: In this paper a spray behaviour based on digitalised images is presented for a specific fluid the working range of a spray, the main parameters indicating the spray performances, e.g DeLavan data sheet, cone angle, supply pressure and mass flow rate are defined. Such parameters determine the spray behaviour but they don’t give any answer about the main parameter whose variation determines a different pattern of the atomization. To atomize a high viscous fluid and to achieve an efficient lubrication, the drops of the spray jet have to coalesce and form a continuous liquid film in a very short time. To achieve this kind of behaviour the spray has to generate the droplets in a particular range of diameters so, their deformation after the impact, have to minimize the coalescence time. In this paper the behaviour of a pressure swirl spray working with a high viscous fluid its spectra of droplets and a numerical simulation of the internal flow are presented.
TL;DR: In this article, the influence of different rain rates on the aerodynamic performance of the NACA 0012 airfoil with a low Reynolds number of 1×105 was investigated.
Abstract: The influence of different rain rates on the aerodynamic performance of the NACA 0012 airfoil with a low Reynolds number of 1×105 was investigated. Wind tunnel tests were conducted to determine lift and drag coefficients at various angles of attack in both dry and wet conditions and the results were compared to show the effects of Liquid Water Contents (LWC) at airfoil performance. Four different rainfall rates were simulated by injecting water droplets from commercial rain simulation nozzles upstream of the airfoil model, corresponding to LWCs of 20.548 g/m3, 37.745 g/m3, 41.096 g/m3 and 75.491 g/m3. A computational fluid dynamics code was utilized to gain further knowledge on the flow field. The simulation of rain was accomplished by using the two-phase flow Discrete Phase Model. It was concluded that degradation of aerodynamic performance increases with increasing LWC up to stall angle and stall is delayed for all rain rates. The computational results showed that larger droplets were more susceptible to droplet breakup than smaller droplets and generally breakup near regions with severe pressure gradients, close to the airfoil. The water film height and the location of rivulet formation on the upper surface of the airfoil are also presented.
TL;DR: In this paper, the coexistence of several periodic orbits characterized by different numbers of impacts per period is shown to be a fundamental mechanism in organizing the system dynamics, and the presence of damping due to squeeze oil effects is taken explicitly into account.
Abstract: This paper is concerned with the analysis of systems with gears. An experimental set-up is presented to study the complex behavior exhibited by this class of dynamical systems, focusing in particular on all those phenomena associated to noisy operation. Specifically, using an appropriate model of the experimental rig, the coexistence of several periodic orbits characterized by different numbers of impacts per period is shown to be a fundamental mechanism in organizing the system dynamics. The system of interest is characterized by helical involute tooth pairs. The presence of damping due to squeeze oil effects is taken explicitly into account. The aim is to uncover the effects of such damping on the complex behavior exhibited by the system. Preliminary two-parameter bifurcation diagrams will be presented together with phase space trajectories to support the analysis.
TL;DR: In this paper, the authors present a study on characteristics of mainly hammer head at increased flow demand in pipeline networks using HAMMER software, where the parameters of the pipes, junctions and other elements were inserted in the above software according to the layout of distribution network of Dhapa water treatment plant, Kolkata Municipal Corporation, West Bengal, India.
Abstract: With the increase demand of water in an urban area it becomes necessary to increase the capacity of the water pipeline networks by keeping the pipes and valves elements unchanged as it is very difficult work to change those in an urban area due to inaccessibility. This paper presents a study on characteristics of mainly hammer head at increased flow demand in pipeline networks using HAMMER software. For modeling the pipeline distribution networks, the parameters of the pipes, junctions and other elements were inserted in the above software according to the layout of distribution network of Dhapa water treatment plant, Kolkata Municipal Corporation, West Bengal, India. The flow capacity of the pipeline networks were increased in the order of 25 percent, 50 percent, 75 percent and 100 percent more than the existing flow capacity of the above networks and the transient analyses were done accordingly. Increasing trends of hammer head, pressure and circumferential stress with respect to increased flow demand were observed for all the zones which satisfy the basic equation for water hammer theoretically. It was also checked whether the pipes are safe for taking the load of increased flow demand.