Flow and heat transfer characteristics required for computer simulation of screw compressors are experimentally obtained and used in performance prediction, where the working medium is air. The heat transfer coefficient is determined from the experimental relation between the volumetric efficiency and the inlet temperature. Flow coefficients are obtained from the efficiency-clearance curves. Applying those coefficients to the performance simulation, good agreement is obtained between the tested and calculated performance of three different prototype air compressors. A new rotor profile aimed at higher performance is designed based on the simulation results. The tested performance of the new profile compressor is much higher than that of a conventional compressor, as predicted by the simulation. The new profile compressor has been applied to a commercial series of packaged air screw compressors.

Performance analysis of an oil-injected screw compressor and its application

Many papers exist in the literature that deal with the twin-screw compressor. This usually has two different rotors, a male and a female, and is commonly used to produce compressed gas for ...

Analytical model of a particular type of positive displacement blower

Part 1 of this paper describes the origins, principal developments, characteristics, applications and current competitive position of the twin helical screw compressor. It is now the prefer...

The twin helical screw compressor Part 1: Development, applications and competitive position:

Thermal effect of lubricating oil in positive-displacement air compressors

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Exact Analytical Representation of Screw Compressor Rotor Geometry

Thermodynamic efficiency of the compression process in oil-flooded screw compressors depends greatly on the oil-gas heat transfer process. The amount of heat transfer is a function of many parameters such as mode of oil injection, oil inlet temperature, etc. This paper describes a mathematical model to calculate this heat transfer, assuming that the oil is injected in the form of non-interacting spherical droplets. The droplet trajectories are calculated from the point of injection to the point where the droplets hit the moving boundaries of the compressor rotor. The overall heat transfer is calculated by summing the heat exchange over all the droplets during their free-flight time. This model is then used to calculate the effect of such heat transfer on compressor performance. Some guidelines on ways to enhance heat tran~fer are also provided.

/pdf/heat-transfer-in-oil-flooded-screw-compressors-iw9sxjfj37.pdf

Heat Transfer in Oil-Flooded Screw Compressors

The performance of oil-flooded screw comp ressors depends on a large number of design paramet ers such as rotor profile, number of rotor lobes, rotor L/D ratio, wrap angle, geometrical clearance s, quantity and location of oil injection, discharge port size and tip speed. Knowledge of the effect of these parameters can help a designer to select the best performing machine for a given application. This paper systematically examines the effect of sev eral of the above parameters on compressor size and performance for a given displacement. Proprietary com puter programs (1,2) are used to calculate the geom etrical characteristics of the rotors and compressor p erformance. Results show that the performance can be c onsiderably improved by proper selection of design parameters. Several plots showing the relationship be tween these parameters and compressor size and perfo rmance are presented that could be very valuable to a designer.

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J. L. Bowman

Papers

Heat Transfer in Oil-Flooded Screw Compressors

Effect of Design Parameters on Oil-Flooded Screw Compressor Performance