Faculty Publications

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    Performance Evaluation of Single Pass Solar Air Heater with Stepped-Type Arrangement of Metal Foam by a Numerical Study
    (Springer Science and Business Media Deutschland GmbH, 2024) Diganjit, R.; Gnanasekaran, N.
    A solar air heater is easy to build and easy to use for drying applications, room heating purposes, etc. In the present study, single-pass forced convection rectangular-type solar air heater is studied numerically. The copper metal foam with 0.92 porosity is used for case (a) empty channel, cases (b) to (e) comprising of different stepped-type arrangements, and case (f) fully filled metal foam condition and studied numerically to obtain outlet temperature, pressure drop and the performance factor of the solar air heater. The Reynolds number is varied from 4401 to 5868. Based on this range of Reynolds number RNG k-ε model with enhanced wall function is adopted for numerical simulations. The local thermal equilibrium model is used to simulate the porous zone. The Rosseland radiation model has been chosen with solar ray tracing method. The case (c) is the best stepped-type arrangement to get same outlet temperature compared to fully filled metal foam case (f). Hence, the material cost is minimized. The temperature rise is 8.89% more compared to empty channel solar air heater. Case (c) has less pressure drop compared to other metal foam arrangements. The performance factor for case (c) is 2.03. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Numerical Study for Enhancement of Heat Transfer Using Discrete Metal Foam with Varying Thickness and Porosity in Solar Air Heater by LTNE Method
    (MDPI, 2022) Diganjit, R.; Gnanasekaran, G.; Mobedi, M.
    A two-dimensional rectangular domain is considered with a discrete arrangement at equal distances from copper metal foam in a solar air heater (SAH). The local thermal non-equilibrium model is used for the analysis of heat transfer in a single-pass rectangular channel of SAH for different mass flow rates ranging from 0.03 to 0.05 kg/s at 850 W/m2 heat flux. Three different pores per inch (PPI) and porosities of copper metal foam with three different discrete thicknesses at equal distances are studied numerically. This paper evaluates the performance of SAH with 10 PPI 0.8769 porosity, 20 PPI 0.8567 porosity, and 30 PPI 0.92 porosity at 22 mm, 44 mm, and 88 mm thicknesses. The Nusselt number for 22 mm, 44 mm, and 88 mm thicknesses is 157.64%, 183.31%, and 218.60%, respectively, higher than the empty channel. The performance factor for 22 mm thick metal foam is 5.02% and 16.61% higher than for 44 mm and 88 mm thick metal foam, respectively. Hence, it is found that metal foam can be an excellent option for heat transfer enhancement in SAH, if it is designed properly. © 2022 by the authors.