Technical Papers and Presentations

A wide variety of engineering applications, such as electronics, solar collectors, and internal combustion engines produce heat. This heat can be a positive or negative aspect for a particular application. Enhancing heat transfer has encouraged many researchers to investigate various techniques. In conventional pipe flows, for instance, the straight pipe profile has not satisfied the rise in cooling/heating performance requirements. As a result, an effective configuration improvement technique, such as manipulating the pipe shape, is required. This technique is quite attractive for thermal management of pipe flow especially in applications with limited space. Moreover, the double pipe heat exchanger has been one of the most common heat transfer equipment in many industrial and engineering applications for decades. This configuration has been addressed for many years to maximize heat transfer despite the rise in pressure drop which is a conjugate constraint. The present work aims at utilizing the convergence concept and the wall profile manipulation to introduce and analyze the flow and heat transfer, employing conventional and nano fluids, in innovative convergent pipes and double pipe heat exchangers. Our numerical results, from COMSOL Multiphysics® software, show that increasing convergence angle, Reynolds number, concavity of the convergent pipe wall, volume fraction of nanoparticles, and contraction ratio augments heat transfer. Further, the concave wall profile of the convergent pipe shows a prominent enhancement in heat transfer up to 41%; while, the convex wall profile provides a sustainable and superior performance factor up to 1.223 compared to the straight one, respectively. A modest rise in heat transfer and pressure drop has been observed when the nanoparticles volume fraction increases; thus, the addressed configuration improvements play a crucial role in augmenting heat transfer more than employing nanofluids. In addition, the convergent double pipe heat exchanger (C-DPHE) has a prominent and sustainable performance, compared to the conventional double pipe heat exchanger (DPHE), with an enhancement in heat transfer rate up to 32% and performance factor (PF) higher than one. The optimal operating conditions of the C-DPHE can be established utilizing the comprehensive information provided in this work.