Acoustic Emission Measurement of Flow Transition in Cross-Corrugated Channels

Study of transition from laminar to turbulent flow in a cross-corrugated channel can assist researchers, and designers and manufacturers of cross-corrugated plate heat exchangers with their endeavours to improve the thermal and hydraulic performance of these units. The conventional methods of study of flow transition in a channel involve insertion of a probe into the flow to measure pressure, temperature and/or velocity of the flow. The probe may not only disturb the flow but also it may not be physically possible to place the probe inside the channel under investigation due to its small size. Therefore, in this paper, a non-invasive acoustic emission measurement technique is described, and the results of the flow transition in two cross-corrugated channels are presented. These results are compared with similar experimental data obtained by heat transfer and pressure loss measurements in such channels. Good agreement is reported. The acoustic emission measurement technique being non-intrusive, can be applied to various areas of research where flow disturbance must be avoided.