Positive Displacement Machines, Roots blower, Leakage Flows, Temperature Field, Planar Laser Induced Fluorescence
Investigation of leakage flows in oil-free rotary positive displacement machines (PDMs) is necessary to get a real insight into attributes of leakage flows. Experimental study of heat transfer in the leakage flows of the oil-free positive displacement machines is challenging. The primary reason is complexities associated with actual machine running condition such as extremely small (micron-size) clearance gap, high speed of rotors, optical access of flows etc. Therefore, this studypresents the development of state-of-the-art experimentalsetup usingPlanar La ser-Induced Fluorescence (PLIF) technique to visualize the temperature field in the clearance flows of rotary machines. This study considers Roots blower to implement PLIF technique because it provides relatively easy optical access. Besides, it is a good representative of PDMs. Selection criteria of optical glass, suitable tracer particles, Imaging camera, optical lenses and filters are investigated in detail. Pixel Intensity was found to be conformable in the clearance gap from recorded images of temperature field, thereby confirmed the efficacy of the flow visualization and instrumentation systemsdeveloped.