Study about Optimization in Helical Grooved Tubes for Heat Transfer Enhancement Using Interdisciplinary Techniques

In this chapter, the thermal enhancement factor is examined numerically based on D-optimal design and then the entropy analysis is done on the optimized geometry. Optimization is now a frequently used tool in engineering design. Under a certain set of variables and constraints, optimization is usually done by defining a function of an output variable and thereby determining its maximum or minimum or say, the optimized point. Efforts are being made to enhance the inner tube, shell, or plate design in heat exchangers as well, where much study is being done to maximise efficiency. The surface improvement has been actively investigated in this regard in recent decades. This sort of augmentation is usually dominant on the tube side. In this paper, with the optimization in view, the design is based on interdisciplinary fields. That is, first a numerical study is performed on the helically grooved tubes to examine the thermal enhancement factor. By comparing the entropy-generation rates of the smooth and grooved tubes, this analysis was conducted. The optimum Reynolds number for that tube is the one at which the lowest entropy-generation-rate is reached. Numerical results are initially validated with published experimental results. The chosen optimised tube is next subjected to an entropy minimization analysis including the Reynolds number based on the D-optimal design for the thermal enhancement factor. The tube that has the most grooves, the most depth, and the smallest pitch exhibits the best performance. However, the optimum Reynolds number is at the point where the tube has the least entropy generated as compared to the smooth tube.