Experimental investigations of thermo-exergitic behavior of a four-start helically corrugated heat exchanger with air/water two-phase flow

The present study provides experimental results of the thermal and exergitic behavior of horizontal four-start helically corrugated heat exchanger with none-boiling air water two-phase flow as the working fluid. Due to the ejection and throttling effect at corrugated tubes, the quality and quantity of flow inside corrugated tubes are significantly different from those in smooth tubes. The corrugated tube was put under constant heat flux. The heat flux was employed via heater wire. The inlet, outlet and wall temperature of the corrugated tube were measured to calculate the heat transfer coefficient of the corrugated tube. The superficial liquid Reynolds number (Re-sl) was between 4500 and 14500, and the gas superficial Reynolds (Re-sg) number was between 95 and 500. The results showed that the variation of both the superficial gas and liquid Reynolds number have significant effect on the thermal and exergitic behavior of the helically corrugated tube with air-water two-phase flow. Moreover, increment in the superficial gas Reynolds number makes increment at the overall heat transfer coefficient and exergy destruction. It was also found that the increment of the superficial liquid Reynolds number up to 11128 causes increment at both the overall heat transfer coefficient and exergy destruction. The maximum increment was related to superficial liquid Reynolds number equal to 11128 and was %19 and %32 for the heat transfer coefficient and exergy destruction respectively.