Experimental investigation on heat transfer and pressure loss characteristics of the grooved helically coiled tube heat exchanger

Helically coiled tube heat exchangers have long been a subject of intense research due to their compact structure and efficient heat transfer capabilities. To further augment their performance, this study proposes a grooved helically coiled tube heat exchanger and establishes an experimental platform for a comparative analysis against a conventional helically coiled tube heat exchanger. Through the utilization of water and steam as working fluids, a comprehensive series of experiments was conducted to investigate heat transfer and pressure drop characteristics. Applying the Wilson plot method, heat transfer coefficients were computed for both the tube and shell sides. The experimental results demonstrate that the maximum relative error of tube-side pressure drop in comparison with empirical correlations does not exceed 24%, while the average error for the tube-side heat transfer coefficient is approximately 13%. Moreover, heat transfer coefficients on the shell side can increase by up to 69%, albeit with a significant rise in pressure drop, reaching up to 96%. By employing heat exchanger effectiveness as a comprehensive criterion, the grooved helically coiled tube heat exchanger's effectiveness can increase by up to 23%. These outcomes suggest that the external grooves can effectively amplify the heat transfer efficiency of helically coiled tube heat exchangers.