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Prediction of Interlobe Leakages in Screw Compressors
Author(s): Hitesh Patel, Vikas Lakhera
Keywords: Interlobe clearance, Nozzle equations, Flow coefficients, Leakage flow, Compressor
The clearance gaps in twin-screw compressors are critical for their performance and reliable operation, as the leakage flows through these clearances influence the volumetric and adiabatic efficiencies. The amount of leakage flows depends on the clearance size and shape as well as various geometric and operating parameters. Usually, the isentropic nozzle equations along with appropriate flow coefficients are used for more accurate estimation of the leakage flow rates through the clearance gaps. Hence, a proper understanding of the flow coefficients and their relationship with the dimensionless parameters (such as pressure ratio, Reynolds number, beta ratios) is critical for an accurate prediction of the leakage flows. In the present study, considering the interlobe clearance gap in screw compressor in terms of rectangular openings, the interlobe leakage flow rates are estimated for various opening sizes and pressure conditions using isentropic nozzle equations and an iterative method. The flow coefficients are determined by comparing the experimental values obtained using a specialized test rig and the flow rates obtained from the analytical methods. The dimensionless parameters are varied to see their individual effect on the leakage mass flow rates and on the flow coefficients. The mean deviation from the experimental results when using an analytical iterative procedure (-8.5%) is substantially lower in comparison to the mean deviation (+26.8%) using the isentropic nozzle equations. The study validates that the iterative method can be preferred (for an interlobe leakage flow rate prediction) over the isentropic nozzle equation method.

Journal of Applied Fluid Mechanics

The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating.