Visualization of flat-plate oscillating heat pipe by infrared thermal imaging

In this paper, the flow patterns of flat-plate oscillating heat pipe (FPOHP) at different operation stages were analyzed by infrared thermal imaging. The FPOHP with a working fluid of HFE-347 and a heating power of 20W to 140W was placed vertically. A high speed camera is used to record the flow direction and state of the working fluid in the FPOHP, and the temperature distribution of the FPOHP at different operation stages is recorded by infrared thermal imager. The experimental results show that the flow pattern of the FPOHP can be divided into non-oscillation stage, transition stage and stable operation stage according to the different flow state of working fluid. The temperature distribution presented by infrared thermal image is synchronous with the wall temperature fluctuation of FPOHP and the change of the working fluid flow direction. The flow pattern of the working fluid and the heat transfer performance of FPOHP can be qualitatively judged by infrared thermal imaging.