The Effect of Clearance on Energy Dissipation for the Roots Power Machine Based on Low-Quality Energy Recovery

As a new type of waste heat conversion machine, the roots power machine can convert low-quality waste heat resources that are difficult to use into mechanical energy. In order to study the influence of tip clearance and radial clearance on the roots power machine, experimental studies were conducted with the roots power machine having different combination of tip and radial clearances and their influence on the performance of the roots power machine was examined. A parametric study was undertaken using CFD to find the sensitivity of these clearances in influencing the performance of roots power machine in the range of 0.2-0.5 mm. From the analysis, it was inferred that radial clearance was sensitive for clearance range of 0.25-0.5 mm and tip clearance in the range of 0.2-0.25 mm. Reduction in clearance from 0.5 mm to 0.2 mm caused an increase of 10.368 and 11.423 % in mechanical and volumetric efficiency respectively.