The Performance of the hairpin type U Shape Double pipe heat exchanger type under effect of using Passive and Active Techniques.

The process of improving and developing heat exchanger performance has received a lot of attention, and efforts are still being made by specialized researchers and engineers with a huge investigations to increase rate of heat transfer to lessen the volume size and price cost of the factories apparatus accordingly. In this experimental study, a suitable heat exchanger equipped with flow meters and thermocouples for measuring flow rates and temperatures was used with the U shape hairpin type exchanger. The bending and angle of curvature of the tubes causes vortex flow, which greatly aids to attractive the rate of heat transfer process and increase the performance, The effect of active and passive techniques with different positions of the U shape Exchanger like position (U shape and Inverse U shape ) as parallel coupling with tube liquid in series is investigated during this study. passive technique represented using the O ring fin type. and an active technique represented by the injection of an air bubble by a small compressor through a special air diffuser. The results show that the best application was with inverse U shape (∩) and the performance enhanced about (19.1%) in the case of active techniques while and (11.1%) with passive techniques and by applying both techniques together, the overall enhancement was (30.272%), So this study provides new visions for further studies.