Showing papers on "Diffuser (sewage) published in 2020"

Fast laser speckle suppression with an intracavity diffuser

Abstract: Abstract Fast speckle suppression is crucial for time-resolved full-field imaging with laser illumination. Here, we introduce a method to accelerate the spatial decoherence of laser emission, achieving speckle suppression in the nanosecond integration time scale. The method relies on the insertion of an intracavity phase diffuser into a degenerate cavity laser to break the frequency degeneracy of transverse modes and broaden the lasing spectrum. The ultrafast decoherence of laser emission results in the reduction of speckle contrast to 3% in less than 1 ns.

High Dimensional Matching Optimization of Impeller–Vaned Diffuser Interaction for a Centrifugal Compressor Stage

Abstract: The matching and interaction between the impeller and vaned diffuser is the most important aerodynamic-coupling between the components of a high-speed centrifugal compressor. Many research studies have been carried out during the last decade, both experimentally and numerically, on the flow mechanisms underlying impeller–vaned diffuser matching and interaction, with the aim of achieving a high-performance stage. However, the published work lacks any study that optimizes the matching of the impeller–vaned diffuser components in the environment of a full compressor stage due to two unresolved issues, i.e., identifying an effective matching optimization strategy and the high dimensional nature of the problem. To tackle these difficulties, four different optimization strategies (i.e., (1) integrated, (2) single component, (3) parallel, and (4) sequential optimization strategies) have been proposed and validated through a high dimensional matching optimization of the Radiver compressor test case published by the Institute of Jet Propulsion and Turbomachinery at Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University. Particular attention has been paid to the slope of the diffuser total pressure ratio characteristic near the surge point to further extend the stage surge margin. The results showed that the integrated optimization strategy was the most effective one for achieving good matching of the impeller–vaned diffuser interaction due to its inherently strong coupling optimization. Compared with the baseline compressor, the optimized stage achieved a gain of 1.2% in total-to-total isentropic efficiency at the peak efficiency point as well as a predicted 26.17% increase in stable operating range. For the stage examined in this study, a fore-loaded design of impeller blade as well as an increased vane angle for the diffuser vane was beneficial to the impeller–vaned diffuser matching. The more uniform spanwise distributions of the impeller discharge flow angle and the diffuser vane incidence presented the opportunity for a more optimized matching of the flow field between the 3D impeller and the 2D vaned diffuser. The outcomes of this work are particularly relevant for the advanced design of high-speed centrifugal compressors.

Plate Heat Exchanger with Diffuser Channels

Abstract: A numerical simulation of the heat transfer in plate heat exchangers with diffuser channels with small opening angles was performed with a three-parameter differential turbulence model supplemented by the transport equation for a turbulent heat flux. It is shown that the amount of heat transferred from the “hot” coolant to the “cold” increases as compared that in heat exchangers with channels with a constant cross section due to the heat-transfer enhancement in heat exchangers with diffuser channels.

Laser Doppler Velocimetry Characterization of Unsteady Vaned Diffuser Flow in a Centrifugal Compressor

Abstract: Modern turbomachinery faces increased performance demands in terms of efficiency, compactness, and pressure-rise. Advancements in computational technology have allowed numerical methods to become the backbone of design development efforts. However, the unique complexities of centrifugal compressor flow-fields pose difficult computational problems. As such, advanced experimental methods must be used to obtain high-quality data sets to further inform, improve, and validate computational methods in complex flow regimes. A recent experimental work on a high-speed centrifugal compressor has provided detailed, unsteady, three-component velocity data using laser Doppler velocimetry. A passage vortex is present, and its nascent tied to the increased incidence at mid-span associated with impeller wake flow. This vortex begins in the hub-pressure side corner and grows to fill the passage and become temporally stable. The vortex development is unsteady in nature, and the unsteady effects persist 40% downstream of the throat. Distinct jet and wake flow patterns from the impeller also do not agglomerate until 40% downstream of the throat. Additionally, the critical impact of the unsteady flow development on the time-averaged flow-field is explained.

Effective Optical Diffuser Based on Interfacial Hydrogen-Bonding Polymer Complexation

Abstract: Optical diffusion is an essential photon management process for various photoelectronic systems. This work proposes an approach to fabricate optical diffuser by interfacial hydrogen-bonding polymer...

Phase-locking System in Fiber Laser Array through Deep Learning with Diffusers

Abstract: A first-ever phase-locking system is proposed in coherent fiber laser array through deep learning (DL) with a diffuser. The simulations have demonstrated that DL is highly effective for accurate and fast phase-locking with a diffuser.

Design and Implementation of prototype model of Smart Diffuser using Smart Phone

Abstract: This paper presented a design and a implementation of prototype model which is the smart diffuser device controlled by using Bluetooth technology in the smart phone. We used the ultrasonic waves oscillator so that the smart diffuser was able to spray oil into a device. The device was developed to find out the high brightness led colors switched during spraying the oil. By using the Li-Po battery of 40mAh capacity, we were able to design this portable device was prolonged available time to use and to solve the charging time problem. We realized the availability of prototype model which is using the Bluetooth Low Energy for operating the low power driving.

CFD Simulation Analysis on Make-up Air Supply by Distance from Cookstove for Cooking-Generated Particle.

Abstract: Indoor cooking is the main cause of particulate matter (PM) within residential houses along with smoking. Even with the range hood turned on, cooking-generated PM can spread quickly into the living room due to the heat generated by the cookstove. In order to improve the PM spread prevention performance of the range hood, a supply of make-up air is needed. Generally, make-up air is supplied through a linear diffuser between the kitchen and living room. In such cases, it is necessary to determine the appropriate location of the supply diffuser. This study evaluates the spread of PM according to different locations of the supply diffuser, which feeds in make-up air. For this purpose, indoor airflow and PM spread were analyzed through CFD (Computational Fluid Dynamics) simulation analysis. By changing the location of the supply diffuser from the contaminant source, PM concentration was analyzed in the kitchen and living room of an apartment house in Korea. Based on the results, the optimal installation location was determined. In this study, 1.5 m from the source was the most effective location of make-up air supply to prevent the spread of cooking-generated particles.

Integration of a transonic high-pressure turbine with a rotating detonation combustor and a diffuser

Abstract: In this paper, a diffuser is used to integrate a transonic high-pressure turbine with a rotating detonation combustor (RDC). The paper focuses on the required design modifications to the turbine endwalls (EW) to enable high efficiency, while preserving the airfoil blade-to-blade geometry. The main challenge is the stator passage unstarting, due to the high inlet Mach number. First of all, steady Reynolds Averaged Navier Stokes simulations were performed to compare the efficiency of turbines with constant-radius EWs to turbines with axisymmetric EWs. A modified EW design prevented the unstarting of the stator passage, enabling a significant gain in performance. Afterward, the influence on the turbine efficiency and damping due to the unsteadiness from the diffuser-like fluctuations of the RDC was evaluated with unsteady Reynolds Averaged Navier Stokes simulations with a mixing plane approach (MPA). Full unsteady simulations were carried out on selected inlet conditions and compared to the mixing plane results. This parametric study provides turbine designers with recommended diffusion rates along the vane EWs. Additionally, we provide guidance on the upstream diffuser design, specifically the required damping and outlet Mach number.

Criteria for the Stability Limit Prediction of High Speed Centrifugal Compressors With Vaneless Diffuser: Part II — The Development of Prediction Criteria

Abstract: The challenge to be able to predict the stability limit in high speed centrifugal compressor is particularly strategic in an initial design phase. Furthermore, to be able to predict the limit massflow rate through the use of simplified numerical models (which does not require excessive computational resources) is very important. In the literature there are several methods to predict the chocking condition, while there is a lack as regards the surge condition. The authors have already presented a criterion to predict the surge line valid for centrifugal compressors with vaned diffuser. Instead those with vaneless diffuser have a very different behavior. For this reason, in the first paper an in-depth fluid dynamic analysis has been carried out, in order to identify the main phenomena linked to the trigger of instability in this type of compressors. This analysis has allowed understanding that the rotational speed is a discriminating factor in the phenomenology. In this second part, using the previous information, different criteria to predict the limit massflow rate for centrifugal compressors with vaneless diffuser are described. All the criteria are based on different simplified CFD approaches that can be routinely used during the design phase.

Flow performance comparison along the centerline in straight and s-shaped diffuser

Abstract: In this paper of the S-shaped diffuser with area ratio (AR) 1.5, an experimental investigation was conducted to analyze the effect of the change in curvature of a straight-wall diffuser. During this study, a Straight diffuser was changed in to a curved diffuser at different angles as their same upper and lower limbs (60/60, 90/90). Profile equations of diffusers were generated with the help of MATLAB/Simulink v2017a software. In this work centerline length is constant for all three profiles, Centerline length that’s utilized in the sector of circle and radius of curvature is calculated. S-shaped diffuser had a different unique angle with square inlet and a rectangular outlet. S-shaped diffuser CPR and CTL results compared with a straight walled diffuser with the different inlet velocity and Reynolds Number. These outcomes from this research obtained the coefficient of static pressure gain and coefficient of total pressure loss for the three profile of the diffuser (Straight, 60/60, and 90/90 S-Shaped Diffuser).

Removal of Pollution by Intensive Aeration Technology for Landfill Leachate Treatment.

Abstract: Background Landfill leachate is a source of environmental pollution and a major concern for human health because it contains high concentrations of organic and inorganic contaminants. Objectives The objective of the present study is to validate the efficiency of the forced aeration treatment technique, which consists of intensively injecting a continuous oxygen flow of 16.75 kg/m3/h for 30 days using a bubble air diffuser in a relatively small volume of 1 m3. The principle of the technique is essentially based on acceleration of the degradation of the effluent as well as reduction of the organic and nitrogenous matter contents. Methods Forced aeration technology was used for the treatment of leachate from the Mohammedia-Benslimane landfill. The sample was treated by injecting a flow of oxygen to accelerate the biodegradability of the pollutants by the microorganisms. Results The physicochemical characterization of the raw leachate at the inlet of the aeration tank showed high values for chemical oxygen demand (COD) (38,600 mg O2/l), biological oxygen demand (BOD5) (24,000 mg O2/l), and total Kjeldahl nitrogen (TKN) (5,932.45 mg/L). The proposed treatment technique allowed relatively high purification yields to be achieved, with abatement rates for the major elements COD, BOD5 and TKN of 73%, 98%, and 85%, respectively. Conclusions The treatment of leachate by intensive aeration technology reduces considerably the pollutant load and achieves a high purification yield. Competing interests The authors declare no competing financial interests.

Clocking effect in a centrifugal pump with a vaned diffuser

Abstract: The performance and service life of centrifugal pumps can be influenced by the clocking effect. In this study, 3D numerical calculations based on the k-omega shear stress transport model are conduc...

Impact of scaling on aeration performance of fine-pore membrane diffusers based on a pilot-scale study.

Abstract: Aeration systems consume a large amount of energy in wastewater treatment plants. Fine-pore membrane diffusers are most commonly used in aeration systems. Scaling and fouling on these membrane diffusers will lead to decreased performance in aeration and increase energy consumption. This pilot-scale study focused on the scaling of the three kinds of fine-pore membrane diffusers under different influent hardness conditions. The results showed that the diffusers were mainly polluted by calcium carbonate scaling. Scaling occurred on the outer surface, orifices and inner surface of the membranes. The dynamic wet pressure (DWP) of ethylene-propylenediene monomer (EPDM), silicone and polyurethane (PU) membrane diffusers increased by 126%, 34% and 304%, respectively, within 50 days when the hardness was 400 mg/L (as CaCO3). However, the increase ratio became obviously slow during the subsequent 60-day operation, indicating a scaling rule of membrane diffusers. Considering that the standard aeration efficiency (SAE) acted as a comprehensive index for judging the aeration performance, the silicone diffuser had better performance than the other two diffusers when severe scaling occurred. This research also provides basic support for the design of membrane diffusers to improve their anti-scaling performance.

Analysis and Optimization of Staggered Partial Diffuser Vanes in a Centrifugal Pump

Abstract: A performance analysis and three-objective design optimization were performed for the staggered partial diffuser vanes in a centrifugal pump using three-dimensional Reynolds-averaged Navier–Stokes equations. First, the performance of the diffuser vanes was evaluated for four different arrangements: full-height diffuser vanes, vaneless diffuser, half vanes attached to the hub, half vanes attached to the shroud, and staggered vanes attached alternately to the hub and the shroud. The staggered partial diffuser vanes were optimized using the following design variables: the installation angle of the vanes, the heights of the vanes attached to the hub and shroud, and the angle of rotation of the straight part on the pressure surface of the vanes. The objective functions were the hydraulic efficiency, the flowrate of the maximum pressure recovery, and the operating range of the diffuser. The Kriging model was used to construct surrogate models of the objective functions based on the results at the design points obtained by Latin hypercube sampling. The Pareto-optimal solutions were obtained by a multi-objective genetic algorithm (MOGA). The representative Pareto-optimal solutions for the staggered diffuser vanes obtained by the K-means clustering showed the improved performances in terms of both the hydraulic performance and operating range compared with the full-height diffuser vanes and the baseline design.

Diffuser for measuring performance of air conditioner

Abstract: The present invention relates to a diffuser for measuring performance (status) of an air conditioner and a risk factor notification system using the same, and specifically, to a diffuser for measuring performance of an air conditioner, wherein various sensors (temperature/humidity/fine dust/other air quality/noise/air volume sensors, etc.) are installed in the diffuser of the air conditioner that supplies or exhausts air, respectively. The temperature, humidity, fine dust concentration, other air quality, noise and air volume, etc. are measured through the air supplied indoors through the diffuser using each sensor, the performance of the air conditioner is collected and analyzed, and then risk factors are determined in advance and provided to a user.

Systems and methods for combustor panel

Abstract: A combustor of a gas turbine engine includes a combustor shell having a diffuser side facing a diffuser chamber and a combustor side facing a combustor chamber The combustor may include a first combustor panel coupled to the combustor side of the combustor shell and a second combustor panel coupled to the combustor side of the combustor shell A gap may be defined between the first combustor panel and the second combustor panel and the combustor shell may include a gap impingement hole that is directly open to and is configured to deliver cooling air directly to the gap In various embodiments, the combustor further includes a throttle plate coupled to the diffuser side of the combustor shell

Personal comfort variable air volume diffuser

Abstract: A method for providing personalized comfort to occupants of an environmentally conditioned space includes sensing a pre-adjustment pressure within a variable air volume diffuser, remotely adjusting a position an individually-adjustable directional outlet of the variable air volume diffuser, sensing a post-adjustment pressure within the variable air volume diffuser, and modifying the airflow through the variable air volume diffuser such that the post-adjustment pressure is equal to the pre-adjustment pressure. The variable air volume diffuser includes individually-adjustable directional outlets and a controller configured to regulate air pressure within the variable air volume diffuser when an individually adjustable directional outlet is adjusted. A user device in operative communication with the variable air volume diffuser includes a user interface to remotely adjust an adjustable directional outlet of the variable air volume diffuser to provide personalized comfort for the user. In embodiments, the variable air volume diffuser responds to spoken commands.

Experimental Study of Vaneless Diffuser Rotating Stall Development and Cell Merging Phenomena

Abstract: This paper describes the vaneless diffuser rotating stall (VDRS) development and cell-merging phenomena. A centrifugal compressor’s lifespan may be limited by flow instabilities occurring in off-design operation. One such instability is the VDRS, which generates oscillating, asymmetrical flow fields in the diffuser and, thus, undesired forces acting on the rotor. Understanding and prevention of VDRS behavior are crucial for achieving safe and undisturbed compressor operation. Experimental measurements of centrifugal compressors operating under the influence of VDRS have been presented. Two different approaches were used for the identification of VDRS: pressure measurements and two-dimensional (2D) particle image velocimetry (PIV). Frequency analysis based on spectral maps and cell development processes were investigated. The presented results showed that mass flowrate has an impact on the rotating frequency of both the entire structure and single cells. Additionally, it affects radial cell size, which grows with compressor throttling and ultimately reaches the length of the diffuser. During the experiments, the cell-merging phenomenon was observed which has not been widely described in the literature. The results presented in this paper allow a better understanding of vaneless diffuser rotating stall behavior. The phenomenon of the change of cell size and frequency could be very important for machine fatigue. Cell-merging could also have an impact on the machine’s vibrations and flow stability. Since it is believed that VDRS is one of the factors inducing surge, its understanding and prevention may have a positive influence on surge margins.

Analysis of Two-Phase Flow inside Porous Diffuser

Abstract: Evaporation process inside diffuser filled with porous medium is numerically investigated. The governing equations have been made dimensionless form and discretised using Finite Volume Method (FVM). Effects of the relevant parameters on the temperature distribution and liquid saturation have been carefully analysed. Numerical results showed that the smoothing treatment of effective diffusion coefficient promote the undesired “jump” in the temperature profile. Furthermore, the inlet Reynolds number, heat flux, outlet radius, length of spread section, and pipe length have a strong effect on the beginning and ending of evaporation process, while porosity and Darcy number have slight influence. Finally, the investigation exhibits a helpful instrument for structuring a diffuser evaporator with goal to hold the system under safety conditions.

System and method for vaporizing cartridge system with diffuser

Abstract: Provided is a system (100) and method (700) for a vaporizer cartridge system (104) wherein the cartridge (104) provides the diffuser (112). More specifically, an embodiment of the system includes a vaporizing device (102) providing a heating element proximate to a removable cartridge system (104) receiving port (804), and a dispenser trigger (132) structured and arranged to engage the removable cartridge (104) to dispense a predetermined amount of a liquid concentrate (110) from within the removable cartridge (104). The system further includes a cartridge with diffuser including: a housing (106); a reservoir (108) of liquid concentrate (110); a diffuser element (112); a metered dispenser (114) structured and arranged to dispense from the reservoir (108) into the diffuser element (112) a predetermined amount of liquid concentrate (110). An associated method (700) of use is also provided.

Optimization of the optical structure of thin direct-lit LED backlights for LCD applications by using micro-LEDs

Abstract: The optimized optical structure of the micro-LED-based direct-lit backlight was investigated through optical simulation. The backlight consisted of only one diffuser plate and an array of micro-LED...

Impacts of blade inlet angle of diffuser on the performance of a submersible pump

Abstract: A diffuser acts as an energy conversion device to improve the performance of a submersible pump The blade inlet angle of a diffuser is the most important geometric parameter that affects the perfo