Showing papers on "Gear pump published in 2011"

The Optimal Design in External Gear Pumps and Motors

Abstract: To improve the system performance of hydraulically assisted mechatronic systems, the research investigates the instantaneous pressure of the meshing action in the external gear pumps and motors. The undesired large pressure overshoots or spikes could be excited by virtue of the sudden volumetric change of meshing pockets. In practice, the spikes cause the gear machines to be noisy, inefficient, and have fatigue problems. The study employs the optimization theorem to analyze the nonlinear dynamical equations to define the instantaneous flow area overlapped by the wear-plate profiles and control volumes. The approach can also be applied to determine the backlash area to avoid large pressure variations between two meshing volumes. System noise may consequently be reduced and the mechanical efficiency is improved in gear machines. However, the volumetric efficiency may be compromised. Thus, all these issues have to be considered to achieve the optimal design.

Dynamic behavior of gear pumps: effect of variations in operational and design parameters

Abstract: This work presents a wide number of results about the influence that variations in terms of operational and design parameters play on the dynamic behavior of external gear pumps. These results are obtained by using a non-linear lumped-parameter kineto-elastodynamic model developed and experimentally assessed with the aim of including all the important dynamic effects. On the one hand, the effects of variations in the operational parameters—namely output pressure, rotational speed and oil viscosity—are analysed; on the other hand, the effects of modifications of some design parameters are shown: clearances and relief groove dimension. The results in terms of gear eccentricity, pressure evolution, pressure forces, gear accelerations and variable forces exciting the pump casing enlighten the dynamic behavior of gear pumps and give useful indications for design improvements and vibration and noise reduction. As regards specifically gear accelerations as well as forces exciting the casing, they strongly increase with both output pressure and rotational speed, but variations in rotational speed in the operational range give lower effects. Conversely, the modifications of the clearances give negligible effects, while the relief groove dimension is very important: the larger the relief grooves are, the higher the gear accelerations and forces exciting the casing become.

Gas turbine engine lubrication

Abstract: A turbine engine includes a fan shaft and at least one tapered bearing mounted on the fan shaft. The fan shaft includes at least one radially extending passage adjacent the at least one tapered bearing. A fan is mounted for rotation on the tapered bearing. An epicyclic gear train is coupled to drive the fan. The epicyclic gear train includes a carrier that supports star gears that mesh with a sun gear, and a ring gear that surrounds and meshes with the star gears. Each of the star gears is supported on a respective journal bearing. The epicyclic gear train defines a gear reduction ratio of greater than or equal to about 2.3.

Optimal rotor wear design in hypotrochoidal gear pump using genetic algorithm

Abstract: The wear rate between the rotors of a hypotrochoidal gear pump is characterized. Using the knowledge of shape design on the rotors, the contact stresses without hydrodynamic effect between the rotor teeth were evaluated through the calculation of the Hertzian contact stress. Based on the above results and the sliding velocity between the rotors, a genetic algorithm (GA) was used as an optimization technique for minimizing the wear rate proportional factor (WRPF). The result shows that the wear rate or the WRPF can be reduced considerably, e.g. approximately 12.8%, throughout the optimization using GA.

Hybrid hydraulic systems for industrial processes

Abstract: A hydraulic drive system for driving a load includes a drive shaft; first and second hydraulic pumps driven by the drive shaft, and a control system that operates the hydraulic drive system in a plurality of modes including: a) a first mode where the second hydraulic pump pumps hydraulic fluid from a supply line to an accumulator; b) a second mode where the second hydraulic pump pumps hydraulic fluid from the accumulator to the supply line; c) a third mode where the second hydraulic pump pumps hydraulic fluid from the supply line to a reservoir; and d) a fourth mode where the second hydraulic pump pumps hydraulic fluid from the reservoir to the supply line. At least the second hydraulic pump is a variable displacement bidirectional pump.

Dual drive pump system

Abstract: A dual drive pump system for rear wheel or front wheel drive automatic transmission in a motor vehicle includes a dual drive pump disposed off-axis of the transmission input shaft axis and driven by a gear train driven by a hub The dual drive pump is also driven by a gear train driven by an auxiliary motor Torque multiplication through the gear train allows the dual drive pump to have a smaller displacement while still providing the hydraulic pressure needs of the transmission The dual drive pump may be driven by either an engine or the auxiliary motor depending on the operating conditions of the motor vehicle

Friction torque characteristics of an internal gear pump

Abstract: This paper describes the influence of pump operating conditions, such as operating pressures, pump speeds, and oil temperatures, on the friction torque characteristics of internal gear pumps for automobiles. Additionally, it presents a new mathematical model reflecting the influence of the oil temperature on the friction torque. In an internal gear pump, the friction torque was affected by oil temperature as well as operating pressure and pump speed. When the operating pressure was high, the influence of oil temperature on friction torque at a pump speed of less than 1000 r/min was contrary to that at a pump speed of greater than 1000 r/min. It was considered that the friction torque is fundamentally composed of three components: the component dependent on the operating pressure, dependent on the pump speed, and independent of both the operating pressure and the pump speed. However, the component dependent on the operating pressure was affected significantly by not only the pump speed but also the oil tem...

Numerical modelling and analysis of external gear pumps by applying generalized control volumes

Abstract: Components in gear pumps usually involve complex geometrical arrangements in order to achieve the desired performance. The use of lumped parametric models is considered the most accurate and effective method for investigation of the associated design issues. In this study, the numerical modelling approach based on the lumped parameters and control volume concepts is reviewed, especially for gear teeth within the meshing zone. To apply the approach to the entire gear pump, control volume concepts are generalized to all gear pockets and flow orifices with some reasonable assumptions. The assumptions include instantaneous angular positions, orifice transitions and imagined control volumes with internal flows. The fluid dynamics and pump performance, which even have the measurement difficulties, can be estimated to investigate and optimize the design parameters of gears by the model. A simulation example and its experimental results of a gear machine are presented to validate the proposed approach in this art...

Electro-hydraulic drive system for a work machine

Abstract: An electro-hydraulic drive system for a work machine which drives an upper rotary body by controlling a flow rate of a hydraulic fluid by a control valve, includes an electro-hydraulic pump including a hydraulic pump driven by an engine, and a first electric motor, and an electro-hydraulic motor including a hydraulic motor rotated by the hydraulic oil supplied from the electro-hydraulic pump, and a second electric motor, and a controller which determines an operating state of the first electric motor and an operating state of the second electric motor based on a load of the electro-hydraulic pump and a load of the electro-hydraulic motor, and is able to perform an efficient operation by using a hydraulic pressure (fluid pressure) and electric power.

A Study of Seal Lubrication in an Aerospace Fuel Gear Pump Including the Effects of Roughness and Mixed Lubrication

Abstract: This article describes a hydrodynamic and elastohydrodynamic lubrication analysis of film generation at the rotating contact between the gear tooth end faces and bearing block thrust face seal in a high-pressure aerospace fuel pump. The analysis includes the effect of tilt of the face seal together with elastic deformation and surface roughness of the contacting components. The results of the analysis show that relatively thin hydrodynamic films are generated and that the most likely mode of lubrication is that of mixed lubrication in which part of the load is carried by direct contact at asperity junctions. It is shown that a small improvement in film formation might be obtained by careful profiling or crowning of the end faces of the gears.

Engine start stop applications for solenoid pumps

Abstract: A solenoid pump and associated hydraulic circuitry are intended for use in automatic transmissions capable of engine start stop (ESS) operation. In a first embodiment, a solenoid pump provides pressurized hydraulic fluid to respective inputs of two way check valves. The other inputs are provided with controlled hydraulic fluid from a transmission valve body. The outputs of the check valves are provided to those hydraulically operated torque transmitting devices associated with first gear. The solenoid pump is activated when the transmission is in gear and the engine is stopped to maintain hydraulic pressure in those actuators associated with first gear in order that a first gear vehicle launch may be quickly and smoothly achieved when the engine is restarted. A second, similar embodiment provides hydraulic fluid to actuators associated with reverse gear. A third embodiment includes a solenoid pump and a latching solenoid valve both communicating with a hydraulic supply between a variable output solenoid valve and a hydraulic actuator in an automatic transmission which maintains clutch pressure by compensating for leaks in the hydraulic components. In a fourth embodiment, a solenoid pump provides pressurized hydraulic fluid to the exhaust backfill circuits of one or more hydraulic operators in an automatic transmission.

Flow characteristics of high-order ellipse bevel gear pump

Abstract: Aiming at the function of variable displacement gear pumps and the application of noncircular bevel gears,a kind of new intersection axis variable gear pump named higher order elliptic bevel gear pump was proposedThe gear pump is a non-circular bevel gear pump which takes the high-order ellipse bevel gear as working rotorThe gear profile formative method of gear rotor can be provided based on the space engagement theoryTransmission characteristic of the pump was analyzed according to the special kinematic traits of ellipse gearAverage theoretical flow formula,instantaneous flow formula and flow pulsation formula of this pump were deduced base on the differential theory of spherical spaceMeanwhile the impact of eccentricity ratio and exponent number on flow characteristic was also analyzedAverage theoretical flow and instantaneous flow of high-order ellipse bevel gear pump were compared with both cylindrical gear one and noncircular cylindrical gear one under the same work condition and similar model parameter,and which shows that the characteristic of high-order ellipse bevel gear pump owns the features of higher delivery and wider range of variation

Wave energy-based gliding propeller

Abstract: The invention provides a wave energy-based gliding propeller. A machine frame is provided with a wave energy conversion device, a storage battery and a gliding propelling control device. A wave sensinThe invention provides a wave energy-based gliding propeller. A machine frame is provided with a wave energy conversion device, a storage battery and a gliding propelling control device. A wave sensing part of the wave energy conversion device comprises an inner frame, a cross shaft, a first vertical shaft, a second vertical shaft and a counter weight, the first vertical shaft and the second vertig part of the wave energy conversion device comprises an inner frame, a cross shaft, a first vertical shaft, a second vertical shaft and a counter weight, the first vertical shaft and the second vertical shaft are connected with a spiral spring torsion power generating part through a motion transmission part and a unidirectional motion conversion part, a gear pump of the gliding propelling controlcal shaft are connected with a spiral spring torsion power generating part through a motion transmission part and a unidirectional motion conversion part, a gear pump of the gliding propelling controldevice is driven by a gear pump motor, the outer layer of a double-layer leather bag is communicated with external water, the inner layer of the double-layer leather bag is communicated with an oil p device is driven by a gear pump motor, the outer layer of a double-layer leather bag is communicated with external water, the inner layer of the double-layer leather bag is communicated with an oil port A of a three-position four-way reversing valve, an oil tank is communicated with an oil port B of the three-position four-way reversing valve, the output end of the gear pump is communicated withort A of a three-position four-way reversing valve, an oil tank is communicated with an oil port B of the three-position four-way reversing valve, the output end of the gear pump is communicated withan oil port P of the three-position four-way reversing valve, the input end of the gear pump is communicated with an oil port O of the three-position four-way reversing valve, the two ends of an overfan oil port P of the three-position four-way reversing valve, the input end of the gear pump is communicated with an oil port O of the three-position four-way reversing valve, the two ends of an overflow valve are communicated with the input end and the output end of the gear pump, the end parts of the cross shaft and the vertical shafts are provided with turn angle control motors. The propeller clow valve are communicated with the input end and the output end of the gear pump, the end parts of the cross shaft and the vertical shafts are provided with turn angle control motors. The propeller can convert wave energy into electric energy and realize gliding and steering by changing the position of the center of gravity and buoyancy force.an convert wave energy into electric energy and realize gliding and steering by changing the position of the center of gravity and buoyancy force.

Case flow augmenting arrangement for cooling variable speed electric motor-pumps

Abstract: Example fluid circuits (e.g., within aircrafts) include first (12) and second (32) pump assemblies. The first pump assembly has an electric motor (18) and a first fluid pump (16). The first fluid pump is coupled to the electric motor and has a case drain port (30) that is in fluid communication with a case drain region of the first fluid pump. The second pump assembly is powered by hydraulic pressure from the first fluid outlet (22) of the first fluid pump and functions to augment flow through the case drain region of the first fluid pump.

Dual drive pump system with one way clutches

Abstract: A dual drive pump system for rear wheel or front wheel drive automatic transmission in a motor vehicle includes a dual drive pump disposed off-axis of the transmission input shaft axis and driven by a gear train driven by a hub. The dual drive pump is also driven by a gear train driven by an auxiliary motor. Torque multiplication through the gear train allows the dual drive pump to have a smaller displacement while still providing the hydraulic pressure needs of the transmission. Each gear train is connected to the dual drive pump via back-to-back one way clutches (OWC). The dual drive pump may be driven by either an engine or the auxiliary motor depending on the operating conditions of the motor vehicle.

Oil pump system for automatic transmission

Abstract: A hydraulic pump system for an automatic transmission has the advantages of preventing excessive power loss and durability deterioration. The hydraulic pump system may include a first hydraulic pump that generates a first hydraulic pressure to supply a low pressure portion with the first hydraulic pump, a second hydraulic pump that receives the first hydraulic pressure to generate a second hydraulic pressure higher than the first hydraulic pressure and supplies a high pressure portion with the second hydraulic pressure, and a drive portion that rotates a drive shaft that integrally connects the first hydraulic pump with the second hydraulic pump.

High-pressure gear pump

Abstract: The utility model discloses a high-pressure gear pump with a double-end-face hydraulic automatic compensation function The appearance of the high-pressure gear pump is of a 'two-piece' structure consisting of a pump cover and a pump body The appearance of the pump body is a cylindrical shell, wherein one end of the cylindrical shell is closed, the other end of the cylindrical shell is opened, the cylindrical shell is combined with the pump cover, and the cylindrical shell is provided with a chamber; a front expanded high-pressure area of a floating side plate of the pump body is lower than the front surface of the side plate, an unloading groove of the high-pressure area is a cat ear-shaped rectangular unloading groove, a lubricating groove on the low pressure side has a low-pressure oil suction and lubrication function and an unloading function, and the front surface of the side plate is also coated with a wear-resistant coating; and the position determination and shape design of a sealing groove on the reverse surface of the side plate and the shape design of an omega-shaped sealing groove facilitate that an active line of a resultant force of pressing forces generated by the back surface of the side plate and an active line of a resultant force of hydraulic reverse thrusts generated on the front surface of side plate are collinear, and the ratio of the two forces is kept within a range of 10-115 According to the utility model, the shaft diameter of the integral gear shaft is designed into an inverted cone shape, and a strong composite sliding bearing is selected, thereby facilitating the improvement of the operating pressure of the pump

Spiral bevel gear set for ram air turbine

Abstract: A ram air turbine (RAT) assembly includes a gearbox that supports a gear set with a ring gear that drives a pinion gear. The gear set provides for the transmission of power from the turbine to a generator, pump or other power conversion device. A turbine shaft supports the ring gear and a pinion shaft that rotates about an axis transverse to the turbine shaft supports the pinion gear. A ratio between a face width and a diametrical pitch of the gear set is within a desired ratio that provides sufficient space for supporting bearing assemblies while providing for operation within the physical constraints and desired performance requirements of the RAT.

Drive assembly for vane pump in gear box of motor car, has electric motor arranged outside gear housing, where drive shaft of motor is sealed by wall of gear housing and arranged axially parallel to main drive shaft and to pump shaft

Abstract: The assembly has an oil pump (2) i.e. vane pump, decoupled from a main drive shaft (4) of a motor car by a freewheel (5). The oil pump is driven by an electric motor (9), where the electric motor is arranged outside a gear housing (1). A drive shaft (10) of the electric motor is sealed by a wall of the gear housing. The drive shaft of the electric motor is arranged axially parallel to the main drive shaft and to a pump shaft (7) of the oil pump. The electric motor and the oil pump are drivingly connected to one another via a flexible drive.

Method for operating rotation speed-variable pump e.g. internal gear pump, involves partly compensating periodical returning troubles by pilot control of rotation speed course to reduce deviation of pump output pressure course

Abstract: Method for operating variable-speed pumps, wherein the pump has a drive device (2) and a control device (4) for controlling this drive device (2), and this control device (4) controls the drive device (2) with a predetermined speed curve such that a characteristic Pump output pressure curve of the pump corresponds to a predetermined target pump output pressure curve and wherein periodically recurring disturbances affect the characteristic pump output pressure curve. According to the invention, these periodically recurring disturbances are at least partially compensated by a pre-defined feedforward control of the predetermined speed curve in order to reduce a deviation of the characteristic pump output pressure profile from the desired pump output pressure curve.

Proportional and hydraulic tracking system for trough solar thermal power generating condenser

Abstract: The invention relates to a proportional and hydraulic tracking system for a trough solar thermal power generating condenser, comprising a condenser board, a supporting board, a collector tube, a cylinder and a hydraulic system of the cylinder. The tracking system is characterized in that the hydraulic system comprises a tank, a motor, a gear pump, a proportional servo directional valve, an accumulator and a solenoid directional valve; the pressure oil in the tank is communicated with the cylinder through three working circulating oil paths after passing through a check valve and a pressed oil filter; in the first path, the pressure oil enters into the proportional servo directional valve via a pressure compensator; in the second path, the pressure oil enters into the accumulator via a safety valve group of the accumulator; and in the third path, the pressure oil enters into the cylinder via a bidirectional hydraulic control check valve after entering into the solenoid directional valve. The tracking system has the following advantages and beneficial effects: the tracking system adopts the servo cylinder and is provided with the grating displacement transducer inside; the display precision of the transducer is 1mu m; the ultimate alternate thrust borne by the system is 15000-20000N (fresh gale); the reciprocating motion distance of the cylinder is 840mm and the speed is 0.03-0.7mm/s; the power of the motor is 0.5kW; and the system can continuously track the sun and carry out automatic adjustment and is provided with the self-carrying air-cooled oil cooler and heater.

Gear pump with three gears

Abstract: The utility model relates to the technical field of gear pumps, in particular to a gear pump with three pumps, which comprises a pump body and a pump cover, wherein the pump body and the pump cover are respectively provided with an oil inlet channel and an oil outlet channel. The gear pump with the three gears is characterized in that three gears are arranged in the pump body side by side, the middle gear is a driving gear, the gears at the two sides of the driving gear are driven gears, and the driving gear and the driven gears are connected with the pump cover through a gear shaft and a bearing. According to the utility model, the driving gear is positioned in the middle position, the driven gears are arranged at the two sides, so two pairs of gears which are meshed with each other are formed, two suction openings and two discharge openings are formed, the flow is correspondingly increased, clearances are kept between the meshing areas and between the pump wheel and a pump shell body all the time when the gear wheel is synchronously rotated and meshed, and the gear pump with three pumps has a simple structure, convenience and quickness in connection and dismantling, balanced axial force of the driving gear, effectively-improved flow, and better improved impulse condition of liquid flow.

Extruder apparatus for forming tire components

Abstract: A method and apparatus for applying a blended rubber composition directly onto a tire building drum or core is described. A first extruder and a first gear pump for a first compound is provided. A second extruder and a second gear pump for a second compound is provided. The output of the first and second gear pump is fed into the inlet of the main extruder. A third pumping means is provided for pumping an accelerator mixture into the inlet of the main extruder; mixing together said first compound and said second compound and said accelerator mixture in said extruder and applying the mixture onto a tire building drum or core.

Pump-jet water propeller system for five-element combined ship

Abstract: The invention provides a structure of a pump-jet water propeller system for a five-element combined ship. A screw pump, a multi-stage series axial-flow pump and other members are optimally combined in the system, which generates a qualitative leap, achieves the purpose of super-powerful water-jet propulsion, meets the requirement of super-powerful propulsion for various modern high-speed ships and the requirement of energy saving, and eliminates the fatal flaws of water-jet propulsion using a screw propeller or a single axial-flow pump or mixed-flow pump in terms of principles. The five innovation points are as follows: a first element is a pre-mounted multi-stage dual-circular arc gear pump which is used for guaranteeing and increasing pressure and speed, a second element is a screw pump, a third element is a multi-stage axial-flow pump, a fourth element is an air/water co-jet boost structure and a fifth element is a guide pipe which is mounted at a jet mouth to achieve the energy saving effect. The two independent pumps are arranged inside a cabinet and produce less noise. The pump-jet water propeller system is suitable for being set with a super-high power to support the large-sized and high-speed ships. The third element, the second element and the first element are assembled in sequence to form an air pump for ships. The pump-jet water propeller system is applied to the development and application of the high-speed ships and can promote the development of related industrial chains.

System and method for controlling hydraulic system based on temperature

Abstract: A hydraulic system includes a hydraulic transmission including a hydraulic pump configured to be coupled to a prime mover, a hydraulic motor configured to be coupled to an output shaft, and fluid lines coupling the hydraulic pump to the hydraulic motor to provide a fluid circuit providing flow communication between the hydraulic pump and the hydraulic motor, such that operation of the hydraulic pump provides fluid flow to the hydraulic motor, and the hydraulic motor supplies torque to the output shaft. A controller is configured to control operation of the hydraulic transmission. The controller is configured to receive signals indicative of pressure in the fluid circuit and reduce an output of the hydraulic pump when the pressure in the fluid circuit reaches a pressure level, and a rate of response of the reduction of the output of the hydraulic pump is varied based on a temperature of fluid in the fluid circuit.

Stainless steel magnetic transmission gear pump

Abstract: A stainless steel magnetic transmission gear pump mainly solves the problems that the existing gear pump has poor sealing property and can not realize automatic pressure relief to easily cause damage to a pump body, a pipe and other related components. The stainless steel magnetic transmission gear pump is characterized in that a motor (11) drives an outer magnetic rotor (12), an inner magnetic rotor (10) and a gear pump to work, generated high-pressure liquid is conveyed by a spacer sleeve (13) under sealing condition, a front seat (1) of the pump is internally provided with a channel (14), two ends of the channel (14) are respectively communicated with an inlet chamber (8) and an outlet chamber (9), and a safety relief valve is arranged in the channel (14). The gear pump adopts magnetic transmission, does not have dynamic seals, and can not generate leakage or pollution, thus satisfying environmental requirements of petroleum, chemical industry and various hydraulic systems. When the pressure at an outlet of the gear pump reaches a preset limit value, the safety relief valve automatically opens to realize automatic pressure relief, thus being safe and reliable without causing damage to the pump body, the front seat of the pump or related components due to too high pressure.

External Gear Pump

Abstract: An external gear pump capable of achieving both a sealing property and a sliding property is disclosed. The external gear pump includes a pair of rotating shafts that are respectively pivotally supported by bearings provided in a casing; at least a pair of gears that are respectively fixed to the pair of rotating shafts and are externally meshed with each other; a side plate that is provided in sliding contact with one side surfaces of the pair of gears; and a seal block integrally including a side surface sliding part and a tooth tip sliding part. The external gear pump further includes movement restrictors on both sides of a straight line connecting axes of the pair of gears, and the movement restrictors restrict the seal block from moving with respect to the casing on a plane orthogonal to the rotating shafts.

Influence of design of hydraulic components on their operation in low ambient temperatures

Abstract: In many machines and devices there are hydraulic drives. They should operate well in various weather conditions, also in low ambient temperatures. Some malfunctions may occur during operation of hydraulic system in a so called “thermal shock condition”, which happens when frozen hydraulic component (e.g. hydraulic pump, motor or directional spool valve) is suddenly supplied with hot oil. Transient thermal state emerges in these conditions. Particular elements of component warm up differently. This results in different thermal expansion of components during warm up, which is changing the size of clearance between cooperating elements. Experimental tests of hydraulic components in low ambient temperatures were conducted in the hydraulic laboratory of the Faculty of Mechanical Engineering of Gdansk University of Technology. They concerned: orbital motors, satellite motors, gear pumps, spool valves (also proportional), piston pumps, and hydraulic cylinders. It was proved, that in thermal shock conditions some malfunctions may occur, especially with large temperature differences between oil and component. Based on results of the tests of hydraulic components and systems start-up in low ambient temperatures, one can perform a change in components design, change the type of material of components elements, and even prepare a proper procedure to be followed during start-up of cold hydraulic components and systems. In the article discusses some designs of hydraulic components resistant to thermal shock, and how to prepare components to work in low temperatures, e.g. by providing system with an additional heater to ensure uniform heating of elements in components. Change in design of hydraulic components resistant to thermal shock conditions can be obtained through computer simulation method. Analytic and computer simulation methods can be used by engineers who design machines and devices that work in low ambient temperatures.

Extending the role of computational fluid dynamics in screw machines

Abstract: Previous publications show that computational fluid dynamics (CFD) can be readily used for the flow prediction and analysis of screw compressors. Several case studies are presented in this article to show the scope and applicability of such methods. These include solid–fluid interaction in screw compressors, prediction of flow generated noise in screw machines, cavitation modelling in gear pumps, and flow in multiphase pumps for oil and gas industry. Numerical grids for all these cases were generated by the authors using an in-house grid generator, while the CFD calculations were performed with a variety of commercially available CFD codes. In order to validate the accuracy of the CFD calculations, an extended test programme was carried out using laser Doppler velocimetry to measure the mean and fluctuating velocity distribution in screw compressor flow domains. The measurement results are then compared with the CFD simulations. The results confirm the viability of the developed techniques. It is shown in this publication that the flexibility of the developed method creates further opportunities for a broader use of CFD for analysis of twin screw machines in a range of new applications.