The use of laser-induced fluorescence to measure temperature in the leakage gaps of oil-free positive displacement rotary machines

Abstract

Positive displacement rotary machines are widely used in industry. Their efficiency is influenced by leakage through the clearance gaps between their stationary and rotating parts. Heat transfer rates between the gas and the machine parts change during the compression process, which can cause differential expansion between them and lead to deterioration of efficiency and reliability. It is necessary to understand the physics of that heat transfer in the leakage gaps.Laser-induced fluorescence has a potential to provide visualization of the temperature field in micron size clearances. However, this technique has not been used before to measure temperatures of a gas in leakages during operation of such machines. The present study describes an assessment of the practical use of anisole-based planar laser-induced fluorescence for the study of the temperature field of leakage flows in the clearance gaps of a Roots blower. The results confirmed the feasibility of its use for this purpose.