Experimental and numerical analyses of the thermodynamic and mechanical performance of an oil-injected and economized 4/6 twin-screw compressor

Abstract

To advance oil-injected twin-screw compressors, it is necessary to understand and model the complex physical phenomena occurring during the compression process (e.g., mass and heat transfer mechanisms) as well as analyze the mechanical behavior of the compressor (e.g., rotordynamics, bearing loads, variation of clearance gaps). To validate these models, the in-chamber compression process as well as mechanical loads need to be accurately measured. This paper presents a comparison between experimental results and numerical modeling of a 4/6 oil-injected twin-screw compressor with slide-valve part-load modulation and economization. The compressor has been equipped with high-frequency pressure sensors, load-cells at the bearings and torque sensor on the main rotor. Bearing forces are analyzed to quantify and validate the experimentally obtained axial force data. The validated model can later be used to analyze the mechanical performance of the compressor, such as bearing loss computation. This study also discusses isentropic and mechanical efficiencies computed for the various data points.