Rotary Vane Compressor Research Articles

Development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane rotary compressors through theoretical and experimental methodologies

The present work highlights the energy saving potential of the lubricant fluid supplied in Sliding Vane Rotary air Compressors. A Lagrangian theoretical model of a sprayed oil injection technology assessed the cooling effect of the lubricant due to the high surface to volume ratio of the oil droplets and predicted a reduction of the indicated power. The model validation was carried out through a test campaign on a mid-size sliding vane compressor equipped with a series of pressure swirl atomizers. The oil injections took place along the axial length of the compressor. The reconstruction of the indicator diagram and the direct measurement of the mechanical power revealed a reduction of the energy consumption close to 7% using an injection pressure of 20 bar. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out to identify an optimal set of operative injection parameters.

Energy saving in sliding vane rotary compressors using pressure swirl oil atomizers

In industrial contexts, electrical energy for compressed air represents an important share of the global electricity consumption: this figure accounts for 4–5% of the total. Among the existing compressor technologies, rotary volumetric machines proved to be more suitable than other types (dynamic, reciprocating, etc.) in terms of pressure and flow rate delivered. Even though not as widespread as screw machines, but thanks to the technological improvements made in the last two decades, sliding vane rotary compressors are characterized by premium specific energy consumptions and demonstrate an unforeseen potential in terms of energy saving due to some intrinsic features specifically related to these machines. The current research focuses on an innovative oil injection technology that is not only able to fulfill the sealing and lubrication requirements but also to cool the air during the compression phase. A comparison between the mathematical model of the new oil injection technology and the experimental p-V diagrams measured through a set of piezoelectric transducers is shown. The compression work reduction, predicted in the model and further measured at the shaft and observed in the indicator diagrams, gives a strong consistency to the injection technology.

Sliding vane rotary compressor technology and energy saving

Energy saving, CO2 reduction, and energy generation from renewable sources represent the three cornerstones of the energetic and environmental commitments of all the countries in the world. These three elements may give a quantitative contribution to the sustainability in an industrial environment. Among them, the most important one, that represents a driver in many sectors, is the limitation of the CO2 concentration in the atmosphere: most recent data (2013) from National Oceanic and Atmospheric Administration – Earth System Research Laboratory (NOAA-ERSL) set at 395.55 parts per million (ppm) the CO2 in the atmosphere and the continuous increasing trend will quickly allow to reach the 450 ppm level which is considered as a safeguard limit to avoid irreversible environmental and socioeconomics problems. Looking at the energy consumption side, energy saving is a key factor. Compressed air production does not escape this requirement and, for the compressor manufacturing industry, this can represent an opportunity with great potential benefits. Compressed air is produced by electrical energy and the consumption accounts as much as 10% of industrial consumption of electricity. A lower estimate places at 6% this share but an additional 12% is estimated to be associated with the commercial and residential markets (portable tools, air pumps, pneumatic heating, ventilation, air conditioning, etc.). Hence, the overall compressor needs are estimated equal to 20% of the industrial electricity needs. Considering that industrial consumption of electricity represents a given share of the overall electrical energy consumption (it depends on the geographical context, social development, industrial level, etc.), with good approximation, compressed air can be associated to the overall electricity consumption and to primary energy consumption too. So, it can be compared with the other energy alternatives when the data are reliable and referred to real situations, actions to promote energy efficiency in compressed air systems can be identified with their real importance and compared with all the other measures. From many independent studies the most important energy saving measures are associated to the: (1) reduction of leakages on the distribution lines, (2) a more appropriate compressed air system design, (3) use of adjustable speed drives, (4) waste heat recovery. All these aspects, in a 10-year period of operation, weigh 70–75% of the overall compressed air costs. Therefore, the compressor technology is a key factor to reduce energy consumption including in it load control, variable speed operation, compressor sizing, etc. A great potential saving is associated to leaks, friction pipes, etc. but these actions are downstream of the compressed air production. After having discussed some issues concerning the future overall energy consumption and CO2 emissions, considering the development of the electricity market in the world in the near future, and overall energy characteristics of existing machines widely used in the compressed air market, the article goes deep inside a specific compressor technology which is represented by the sliding vanes rotary type. Principal processes inside these machines are discussed in the light of the recent scientific literature advancement of a theoretical and experimental nature. The general idea was that these machines are not so well known and their use is not so widespread: thanks to a deeper scientific interest over the past few years, these compressors had a notable performance improvement, thus a greater potential in industrial applications. Thanks to some intrinsic aspects, some energy issues are presented and related to specific processes inside the machine and compared with other compressors. The potential further improvements in terms of specific energy are discussed and addressed in main future research directions.

Friction Analysis on Vane of an Existing and of a Novel Multi Vane Rotary Compressor

This paper presents results of a frictional analysis on a new rotating sleeve multi-vane rotary (RSMVR) compressor. The new five-vane rotary compressor is adapted from the existing concept of a rotating sleeve single-vane rotary (RSSVR) compressor, in which the extended rounded end of one vane is embedded into the inner surface of the sleeve which allows the vane to swing within a certain small angle. As the rotor rotates, this vane drives the sleeve which in turn pushes and pulls the vane into and out of the slot in the rotor, respectively. The other four vanes are similarly pushed into the respective slots in the rotor but slide out only when a sufficient centrifugal force is developed. The driving vane ensures that suction, compression and discharge of the gas occur at all speeds of rotation. Although the sleeve rotates along, due to eccentricity between the rotor and the sleeve, each tip of the four vanes still rubs against the inner surface of the sleeve. The focus of the present study limits its analysis on to only frictions between the vane tip and the inner surface of the sleeve and between the vane sides and the respective slot walls. The frictional analysis is carried out by first determining the instantaneous pressure inside the compression cell and all the associated forces that exist. This involves an analysis on the dynamics of each vane when it reciprocates and at the same time rotates eccentrically with the sleeve. The kinematics of the vane are modelled using cosine and sine rules taking the cell leading vane as a reference to the angle of rotation. In the operation the model estimates a dramatic reduction in friction which is up to 82% lower than that occurs in an existing design of an equivalent conventional multi-vane rotary compressor (MVR). A friction between the rotating sleeve and the two opposite end plates exists in the RSMVR compressor but does not in that of the MVR. This will be included in a later study but on a new integrated brushless DC motor RSMVR compressor concept and on that of the existing shaft driven MVR, to see the overall difference in the frictions exerted.

Interaction between membrane humidifier and air supply system for application of fuel cells in vehicles

The potentialities of a membrane passive humidifier and its interaction with two different air supply devices were examined for application on a PEFC (polymeric electrolyte fuel cell) system to be used in vehicles. A rotary vane compressor was compared to a side channel blower with respect to their capability to assure the correct working of the membrane humidifier in different load conditions. The results obtained on a 12kW stack evidenced that the higher working pressures of the rotary vane compressor permitted improvements in individual cell performance, and determined the possibility to reduce the energy requirements of humidification devices.

Virtual Simulation of Embedded-Vane Rotary Compressor

By using virtual prototype technology, a model of Embedded Vane Rotary Compressor has been established for motion simulation. Based on theoretical analysis and simulation, the motion characteristic, forces and connection constraints was studied and analyzed. The results are helpful for improving the design and performance of the compressor.

Study and Application of the Designing Theory of the Vane Profile for any Rotary Vane Compressor

The vane tip profile contacted with the inner wall of the stator is a key point in designing the rotary vane compressor.The vane tip profile design,matched with the stator profile,closely connected with the essential parameters is presented with the geometric theory of calculus ensuring the reliability of the rotary vane compressor.The theoretical calculation basis is provided for the design of the rotary vane compressor with high efficient compression and the design theory of the rotary vane compressor is broadened.Computer simulation and test demonstrate that the new vane has a better meshing characteristic,which eliminates the scraping between the vane tip and the cylinder and partial abrasion conditions completely,and leads to sliding uniformly.The shape of the vane tip profile ensures the reliability of the seal between the vane tip and the inner wall of the stator;the vane tip profile is simple,and easy to machine.When the vane is meshed with inner wall of the stator,the front and rear transitional arcs smoothly connected with the main vane profile can not only avoid to form a cutting edge shape,but also benefit to form oil membrane.The precision requirement of manufacture and assembly of stator,rotor,vane and rotor slot is reduced.

Modeling of rotary vane compressor applying artificial neural network

The thermal modeling of rotary vane compressor (RVC) was performed in this paper by applying Artificial Neural Network (ANN) method. In the first step, appropriate tests were designed and experimental data were collected during steady state operating condition of RVC in the experimental setup. Then parameters including refrigerant suction temperature and pressure, compressor rotating speed as well as refrigerant discharge pressure were adjusted.With these input values, the operating output parameters such as refrigerant mass flow rate and refrigerant discharge temperature were measured. In the second step, the experimental results were used to train ANN model for predicting RVC operating parameters such as refrigerant mass flow rate and compressor power consumption. These predicted operating parameters by ANN model agreed well with the experimental values with correlation coefficient in the range of 0.962–0.998, mean relative errors in the range of 2.79–7.36% as well as root mean square error (RMSE) 10.59 kg h −1 and 12 K for refrigerant mass flow rate and refrigerant discharge temperature, respectively. Results showed closer predictions with experimental results for ANN model in comparison with nolinear regression model.

Journal bearings design for a novel revolving vane compressor

This paper presents the theoretical details of the journal bearing design for Revolving Vane (RV) rotary type compressor. The mathematical models, force analysis, and the theoretical design analysis for the dynamically loaded journal bearing of the compressor are presented. The variations of the minimum oil film thickness and the maximum film pressure developed are shown and the influences of design parameters, compressor configurations, and operating conditions on the journal bearing performance are described. For an air-conditioning compressor of 1.5 kW cooling capacity, the lowest minimum oil film thickness for lower and upper journal bearings is 6.6 μm and 4.3 μm respectively, when the cylinder is simply supported and the rotor is cantilever-supported. The lowest minimum oil film thickness for the journal bearing, which supports the cylinder, reduces to 4.0 μm if the cantilever-type support is used. Besides that, a short-fat configuration of RV compressor is favorable in the interest of lowering bearing forces.

Mechanical Efficiency Optimization of a Sliding Vane Rotary Compressor

This study presents the mechanical efficiency optimization of a sliding vane rotary compressor by using genetic algorithms. Relevant air properties, volume segments, vane loadings and stresses, friction forces, compression power, and power loss are calculated to determine the mechanical efficiency of a compressor. Design variables include the major axis length and minor axis length of the elliptical stator inner contour, thickness, depth and width of vanes, mechanical efficiency, rotor rotational speed, polytropic exponent, and angular locations of the inlet and outlet ports. The effects of the mutation rate, crossover rate, and population size of the genetic algorithms on these design variables are studied. The vane is thin and the variation effects of vane dimensions on the mechanical efficiency of the compressor are less significant than other design variables. Therefore, the dimensions of vanes can be eliminated as design variables. The mechanical efficiency of the compressor is 0.55. The optimum values of these design variables are recommended for further development of the compressor.

Impact Forces of Sliding Vanes on Rotor Slots in a Rotary Compressor

This study analyzes the impacts of vanes on rotor slots by simulating the impacts of two plates in a sliding vane rotary compressor. The Hertzian contact rule and the first order shear deformation plate theory incorporating the shear deformation and the rotary inertia are used to generate a mathematical model. Impact forces are calculated at various times and positions of the vane. Data generated from the model highly correlated with results obtained from ABAQUS software.

New Curve Vane’s Design Based on Three Circular Arc for Rotary Vane Compressor

The vane tip profile contacted with the inner wall of the stator is the key to design the rotary vane compressor. A new principle and design theory based on the three circular arc(TCA) to design vane profile is creatively presented, it provides a theoretical calculation basis designing the rotary vane compressor with high efficient compression ,and broadens the design theory of the rotary vane compressor. Computer simulation and test demonstrate that the vane based on three circular arc has a better meshing characteristics than the traditional one, it eliminates the scraping between the vane tip and the cylinder and partial abrasion conditions completely, and leads to slide uniformly. The shape of the vane tip profile ensures the reliability of the seal between the vane tip and the inner wall of the stator; the vane tip profile is simple, and easy to machine. When the vane is meshed with inner wall of the stator, the front and back transitional arc smoothly connected with the main vane profile can not only avoid to result the cutting edge shape, but also benefit to form oil membrane, it further improves lubrication conditions and reduces precision requirements of the stator, rotor, vane and rotor slot when machined and assembled.

연료전지용 베인 로타리 공기 압축기 설계

Air supply is required to the cathode of fuel cells for the provision of oxygen to produce electricity through chemical reaction with hydrogen in the cell, and supplied air should be free of impurities such as oil mist and tiny particles separated from sliding surfaces. Hence, air compressor for fuel cell air supply must be oil-less type and have no severe sliding surfaces inside. This paper introduces the concept of single-vane type rotary air compressor whose structure is particularly suitable for the fuel cell application: sliding action of the vane against the cylinder wall, which causes severe friction in the conventional vane rotary compressors, is made to be prevented by attaching the vane to the driving shaft with the compliant device between the vane and the rotor in this new design. For 2 kW fuel cell application, preliminary design has been carried out, and its performance has been estimated by using computer simulation program: for discharge pressure of 2 bar, the volumetric, adiabatic, and mechanical efficiencies are calculated to be 82.5%, 92.5%, and 96.3%, respectively.

Optimal Tolerance Allocation for a Sliding Vane Compressor

An optimization model has been built with consideration of the required reliability, the minimum machining cost, and quality loss. The normal and the lognormal distributions of tolerances that depend on the production types of components are used in the reliability model. Cost tolerance data obtained from Bjørke are used to calculate the machining cost. The asymmetric quadratic quality loss model is used to calculate quality loss caused by the deviation and the mean-shift of distributions. Tolerance allocation of a sliding vane rotary compressor is optimized for the required reliability, the minimum cost and quality loss, and optimum tolerances of components are recommended. The results show that high accuracies of the slot length, the vane thickness, and the slot width are required. Hence, their tolerances are smaller than other components. The effects of the correlation coefficient of the bottom cover plate and the top cover plate and the correlation coefficient of the front cover plate and the rear cover plate to total cost are insignificant. Further, the cost of quality loss is reduced when the weighting ratio of the quality loss function weighting coefficient to the machining cost function weighting coefficient is increased. The total cost is increased because tight tolerance allocation increases the machining cost.

Wrap of cylinder and its effect on main features of rotary vane compressor for automobile air conditioning system

The rotary vane compressor has been used in the automobile air conditioning system. One of the key factors of its design is the wrap of its cylinder. From the working principle of this type of compressor, it is explained in mathematics why the wrap is composed of four parts: arc of circle, main curve, and two segments of transit curves, and the conditions that the wrap needs to satisfy are derived simultaneously. At the same conditions, we compared to the gas force Fp, contact force Fnc of the blade head, the force acting on rotor by blades, and the suction volume Vs for three kinds of main curves. The wrap composed of trigonometric function can form the biggest value of Vs, while the least suction volume Vs will be reached as the cubic polynomial is taken. The wrap composed of trigonometric function forms the biggest absolute value of the gas force Fp and the middle peak value of the force acting on rotor by blades, while the least absolute value of the gas force Fp and the biggest contact force Fnc of blade head will be reached as the cubic polynomial is taken. The force acting on the rotor by blades takes the biggest peak value if the main curve is the ellipse curve. The frequency of the force acting on the rotor by blades is the same as the number of blades at the range of the crank angle from 0 to 180°.

Function‐based flow modeling and animation

AbstractThis paper summarizes a function‐based approach to model and animate 2D and 3D flows. We use periodic functions to create cyclical animations that represent 2D and 3D flows. These periodic functions are constructed with an extremely simple algorithm from a set of oriented lines. The speed and orientation of the flow are described directly by the orientation and the lengths of these oriented lines. The resulting cyclical animations are then obtained by sampling the constructed periodic functions. Our approach is independent of dimension, i.e. for 2D and 3D flow the same types of periodic functions are used. Rendering images for 2D and 3D flows is slightly different. In 2D function values directly are mapped to color values. On the other hand, in 3D function values are first mapped to color and opacity and then the volume is rendered by our volume renderer. Modeled and animated flows are used to improve the visualization of operations of rolling piston and rotary vane compressors. Copyright © 2001 John Wiley & Sons, Ltd.

Performance of a variable-speed inverter/motor drive for refrigeration applications

Presents the results of an experimental investigation into the application of inverter-based variable-speed drives to positive displacement rotary vane refrigeration compressors. The investigation considers the effects of the inverter on a number of operating parameters such as the harmonic currents and voltages on both the supply side and motor side, power consumption and power factor, starting current and overall system efficiency. The results indicate that the use of off-the-shelf inverters for variable-speed control of refrigeration compressors can inject harmonics to the supply system which exceed the maximum limits imposed by BS5406. The inverter may also cause a reduction in the power factor and in the overall efficiency of the drive. Variable-speed operation of a rotary vane compressor may not offer efficiency advantages over fixed-speed operation but can provide other benefits such as better temperature control and faster response to sudden changes in load.

A preliminary evaluation of the Groll rotary vane compressor

The principles of operation and design of the prototype of a novel design of vane compressor with significant advantages over the conventional sliding vane type are described. Its performance is given and compared to that of equivalent commercially available sliding vane and reciprocating compressors used in refrigeration systems. Its volumetric efficiency on average was 3% greater than that of the sliding vane compressor and 23% more than that of the reciprocating machine. The adiabatic efficiency was on average 15% greater than that of the sliding vane and about equal to that of the reciprocating compressor. Owing to its high rotational speed it is more compact than the reciprocating compressor. Since the vanes are rigidly retained about their axis of rotation they cannot chatter as in a sliding vane compressor. It is therefore smooth and quiet in operation and no mechanical faults were encountered in 432 h of operation.

A study on a rotary vane compressor. Flow analysis in the oil separator.

The flow pattern in the oil separator of a rotary vane compressor is studied by the finite difference method. Three-dimensional turbulence flow is calculated in the generalized coordinate. Pressure for the flow field is calculated by the MAC method, and time integration is solved by the Euler's backward scheme. The third-order upwind finite differencing scheme is applied for the convective term in the Navier-Stokes equation. All computations are performed on a FACOM VP 200 supercomputer system. The results of this investigation show that the numerical design is available.

Analysis of a gap flow on the side plate for rotary vane compressor.

The laminar flow of an incompressible Newtonian fluid is considered. A numerical investigation of the pressure distribution between the rotor and side plate of a sliding vane type compressor is studied. Computations of the pressure are performed by the divergence formulation method in general coordinate based on the Kawabata's formulation. These computations are compared with the result of weighted residual finite element method. All computations are excuted on a 32 bits personal computer. So the results of this investigation indicate the posibility that the numerical design by a simple system is useful in the development of this type of compressor.