Optimization and Redesign of Intercooler of Reciprocating Compressor using Analytical and Simulation Approach.

Abstract

Intercoolers are integral part of multistage reciprocating compressors. During compression, the temperature of the air increases, and an intercooler cools the air by removing excess heat from it which results in increase in the density and decrease in the work required for the compression. The performance of the intercooler can be enhanced by changing the design and size of the intercooler. It can also be enhanced by changing the shape and material of the fin. In the present work, the radial fins with different profiles (rectangular, hyperbolic, and triangular) and material having different thermal conductivity (copper, aluminium, and steel) are selected to enhance the performance of the intercooler. The efficiency of a radial fin having a rectangular and hyperbolic profile is calculated using a modified Bessel function by varying radius ratio from 0.1 to 0.9 with a step size of 0.1. The fin efficiencies are presented in terms of radius ratio and the efficiency of fin decreases below 0.5 radius ratio. It shows that as the fin height increases the efficiency of the fin decreases. Fin tip temperature is calculated for rectangle and triangle fin having uniform thermal conductivity. The numerical and analytical results are compared and found in the range of 0.07% to 0.32%. The difference between fin tip temperature and fin base temperature is less for fin having higher thermal conductivity. Also, the rectangular fin has a higher tip temperature compared to the triangular fin for the same material. Numerical results of temperature contour, velocity contour, and pressure contour for the inline and staggered tube are plotted. The heat transfer coefficient is enhanced by 55.78% and pressure drop increase by 63.36% for staggered tube arrangement compared to inline tube arrangement. The plot of heat transfer coefficient versus velocity shows that heat transfer coefficient increases linearly by increasing velocity. The heat transfer coefficient and pressure drop are affected by varying diagonal pitch in staggered tube arrangement. The heat transfer coefficient and the pressure drop are on higher for the smaller size of diagonal pitch.