Experimental studies on parallel wavy channel heat exchangers with varying channel inclination angles

• Experimental studies were performed on five wavy channel heat exchangers.
• The inclination angles between the channels were varied from 0° to 80°.
• It was found that heat transfer increases with cold water flow rate.
• The heat exchanger with 20° inclination showed the highest heat transfer and pressure loss.
• Numerical correlations were developed between non-dimensional numbers.

Experimental studies were performed on corrugated plate heat exchangers. The corrugated plates’ channel inclination angles for the parallel plates were varied from 0° to 80° in increments of 20° in order to experimentally determine the configuration with the optimum heat transfer rate. The channel spacing was kept constant. The media used in both the hot and the cold channels were water. The temperatures of the two media between which heat was exchanged were 25.4 °C for cold water and 38 °C for hot water. The flow in the heat exchangers was parallel with both the fluids entering from the same side. The flow rate of the hot water was kept constant while that of the cold water was varied. The heat exchangers consisted of ten channels, five for hot water and five for cold water. It was found that the rate of heat transfer increases for all the plate inclination angles as the flow rate of cold water is increased. The overall heat transfer coefficient was observed to be the highest for the 20° inclination angle. The low flow rates of the hot and cold fluids make it a unique study, as the two fluids get more time for heat transfer. The 20° channel inclination angle also has the highest average thermal length. Based on the results, correlations between Nusselt number and Reynolds number were developed.