Numerical study of microchamber and cylindrical inserts on enhancement of heat transfer in microchannel heat exchanger

Microchannel heat exchangers (MCHEs) have gained widespread use in electronic devices and are regarded as very effective cooling mechanisms in the current day. The present study focuses on the numerical investigation of the thermo-hydraulic performance of microchannels with microchambers and cylindrical inserts. This investigation is conducted using the finite volume method (FVM) (Ansys Fluent 2022 R1). The examination of microchannels encompasses several facets, such as fluid dynamics, temperature response, pressure characteristics, and criteria for evaluating performance. The findings indicate that the heat exchanger including microchambers and double inserts (referred to as SMCHE-MCDCI) had superior thermal performance compared to the other configurations (SMCHE, SMCHE-MC, and SMCHE-MCSCI). In all instances, the heat transfer coefficient (HTC) and the Nusselt number (Nu) exhibit a positive correlation with the Reynolds number (Re) throughout the range of 74-446. It is found that the HTC increases by 18.88%, 37.86%, and 51.28% in SMCHE-MC, SMCHE-MCSCI, and SMCHE-MCDCI, respectively, when compared with case 1. The formation of vortexes and subsequent fluid mixing in the channel is found to be a result of the combined influence of chambers and inserts. Additionally, it is seen that the pressure rise in SMCHE-MCSCI, and SMCHE-MCDCI is comparatively lower than that in SMCHE-MC, which might be attributed to the presence of inserts. The pressure drop values in SMCHE-MC, SMCHE-MCSCI, and SMCHE-MCDCI is represented in decreasing order by 33.88%, 19.07%, and 10.27%, respectively, compared with SMCHE. It is seen that the overall performance of MCHE with single (SMCHE-MCSCI) and double (SMCHE-MCDCI) cylindrical inserts are increased by 7.18% and 14.57% when compared to without inserts (SMCHE-MC). The best performance is achieved for case 4 (MCHE with microchambers and double cylindrical inserts).