Performance characteristics of shell and helically coiled tube heat exchanger under different tube cross-sections, inclination angles and nanofluids

Abstract

The current research deals with an experimental and numerical inspection of the shell and helically coiled tube heat exchanger (SHCTHE) under various circular, elliptic, and square tube cross-sections. The research study strives to ameliorate the thermal-hydraulic performance with single nanofluids of Al2O3/H2O, MgO/H2O, and TiO2/H2O. Various factors were inspected to consider the heat exchanger performance under parameters, SHCTHE inclination angle, HCT diameter ratio, flow direction, the cross-section geometry shape, nanomaterials type, and nanomaterials concentration. The modeling engaging a numerical code tool of ANSYS-FLUENT 19 was accomplished with a 3D (RNG)/k–ϵ model. The mass flow rate and working fluid temperatures through the coil and shell sides were (0.05:0.2 kg/s at 80 °C and 0.05–0.2 kg/s at 10 °C, respectively. One of the most important results was that the SHCTHE with a circular tube cross-section gave the highest Nusselt number with an approximate percentage of 62.5%. The SHCTHE effectiveness and the number of transfer units were enhanced by around 19.35% and 30.78%, respectively, by the greater HCT diameter ratio and Al2O3 nanomaterials. Nusselt number, friction factor, and SHCTHE effectiveness were correlated through equations (52:55) with dimensionless factors and their limitations.

Keywords

• Elliptic tube
• Square tube
• Shell and helically coiled tube heat exchangers
• Inclination angle
• Nanofluids
• Cooling performance