Study on the Thermohydraulic Performance of Double Pass Solar Air Heater
Abstract
Experimental and numerical investigations are conducted in this study to optimize different turbulence models and thermohydraulic performance of double pass solar air heater (DPSAH) under different Reynolds numbers (Re) of 3000 to 19000. The DPSAH was investigated using five different turbulence models: SST-k-ω, standard k-ω, realizable k-ε, RNG k-ε, and standard k-ε. Using the RNG k-ε turbulence model, the experimental results are found in close agreement with the numerical results, with an average absolute deviation of 2.6% for the Nusselt number (Nu) and an average absolute deviation of 0.4% for friction factor (f). In comparison to single pass solar air heater (SPSAH), the DPSAH enhanced the values of the Nusselt number (Nu) from 1.13 to 1.89 and increased the values of friction factor (f) from 2.69 to 3.5 for a considered range of Re. The maximum thermohydraulic performance parameter (THPP) over the SPSAH was obtained as 1.25, which corresponds to Re of 19000.
Keywords
Thermohydraulic performance, Solar energy, Computational fluid dynamics, Friction factor, Nusselt number