Experimental Study of Heat Transfer Rate in a Shell and Tube Heat Exchanger with Air Bubble Injection (TECHNICAL NOTE)

Shell and tube heat exchangers are widely being used in many of industrial and power engineering applications. Different techniques have been employed in order to enhance the performance of the heat exchanger. Air bubble injection is one method to increase the turbulence of the flowing fluids which in turn enhance the heat transfer performance. Injecting air bubbles is one of the promising techniques which does not require much complex systems. Air can be injected at different points. In this paper, analysis has been carried out for heat transfer performance and exergy analysis with different air injection points. Four different cases with and without air injection in shell or tube side have been taken into consideration and the results are compared. Through the study, it has been observed that injecting air bubbles throughout the tube enhances the heat transfer rate by 25-40% at different range of the Reynolds Number. The effect of air injection at different points also affects the overall heat transfer and the dimensionless exergy loss.