Abstract
Thermohydraulic performance and entropy-generation in a rectangular microchannel for laminar and single-phase flow. • Indigenously developed experimental set-up using piezo-electric micropump. • Sequential switching of the micropump has been done to get continuous flow. • Performing simulations with varying geometry and flow parameters each in 3 levels. • Simulation results validate with experimental results and empirical correlations. • Multi-objective optimization is performed by using response surface methodology. In the present study, thermohydraulic performance and entropy-generation analysis through a single rectangular microchannel is investigated systematically by numerical simulations. The simulations are carried out by considering a three-dimensional thin-wall approximation to avoid the conjugate effect. Here, both the channel width (W) and height (H) are varied as 0.1, 0.55 & 1 mm, and Reynolds number ( Re ) as 150, 600 & 1050, whereas the channel length (L) is fixed to 50 mm. The experiments are conducted for stainless-steel rectangular microchannel of W = 0.35 mm, H = 0.75 mm, and L = 50 mm with DI-water as testing fluid. The simulation results are validated with the present experimental results and the existing empirical correlations. Further extending the numerical simulations, both thermohydraulic performance and entropy-generation have been studied by varying the fluid flow and structural parameters of the microchannel. The results demonstrate that the friction factor value depends upon the aspect ratio (AR) and is independent of channel hydraulic diameter ( D h ), and the channel of AR value of 1 exhibits the lowest friction factor. The average Nusselt number ( Nu avg ) depends upon both AR and D h and the channel having an AR value of more than 1 exhibits higher Nu avg because of higher surface area. The channel D h and flow Re have a significant effect on the total entropy-generation ( S G ), while AR hasn’t had that much impact because by varying AR from 0.18 to 5.5, the S G increases by 5% only. Finally, the multi-objective optimization is carried out by using response surface methodology (RSM) to obtain the optimal design parameter condition, i.e., W = 1 mm, H = 0.63 mm, and Re = 1050, which fulfils the required objective with 0.8254 desirability.
Published Version
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