Abstract
The purpose of this study is to examine the influence of inlet locations on the flow distributions of the multi-channel cold-plates by means of particle image velocimetry (PIV). Unlike the point-wise measurement of velocity, PIV is the newest entrant to investigate the field of fluid flow and provides instantaneous global fields of velocity. PIV records the positions of small tracer particles introduced into the flow to follow the local fluid velocity. Thus, PIV represents a quantitative extension of the qualitative flow visualization techniques that have been practiced for several decades. Basically, the requirements for a PIV system are an optically transparent test-section, an illuminating light source (laser), a recording medium (film, CCD, or holographic plate), and a computer for image processing. Seven inlet configurations (i.e., model-1, model-2, model-3, model-4-normal, model-4-reverse, model-5, and model-6 arrangement) are investigated in this study by means of PIV. In addition to observe the velocity mal-distribution, we also improve the convenience and processing-speed of the PIV post-processing software and introduce a dimensionless parameter（coefficient of variation）to evaluate the velocity mal-distribution and non-uniformity. Furthermore, the pressure drop is the outcome of the velocity mal-distribution such that we measure the corresponding pressure drops for different inlet configurations. As a result of the comparison between the pressure drop and the velocity mal-distribution for the different inlet locations, we can confirm which model has the better flow distribution. In conclusion, model-1 has the maximum pressure drop due to the apparent re-circulation phenomenon on the both sides of the multi-channel cold plate. In contrast with model-1, the velocity mal-distribution and pressure drop of model-5 are minimum among the different cold plates because there is almost no re-circulation phenomenon in every part of the plate even in high inlet flow rate. However, model-4-normal has the corresponding maximum velocity mal-distribution as the impingement effect of inlet flow causes the most part of working-fluid flowing to the outlet directly.