Thermal Performance of Three Sided Artificially Roughened Double Duct Parallel Flow Solar Air Heater - A CFD Approach

Abstract

A sun powered air warmer is essentially a warmth exchanger, which blocks the occurrence sun based radiation changes over it into warm lastly exchanges this warmth to a working liquid for an end utilize system.The method of air streaming in the channels of a sun powered air radiator is a standout amongst the most critical angles worried about sun oriented air radiator which predominantly influence. A twofold pipe parallel stream falsely roughened sun powered air radiator with three sides of the safeguard plate is examined in the present examination. Dissimilar to the ordinary model of sun powered air warmer with just a single sided roughened safeguard plate, a novel sun based air radiator with three misleadingly roughened safeguard plate is utilized so the surface zone of the safeguard plate is expanded which at last builds the rate of warmth exchange. Also, a twofold channel parallel stream game plan through internal and external conduit of sunlight based air warmer is considered request to improve the warmth exchange rate. A numerical examination of the warmth exchange and erosion factor qualities of a twofold pipe parallel stream three sided misleadingly roughened sunlight based air warmer has been completed. A business limited volume CFD code ANSYS FLUENT is utilized to mimic turbulent wind stream through counterfeit roughened sunlight based air radiator. Overseeing conditions of the liquid stream and warmth exchange i.e. Navier-Stokes condition and vitality condition are settled with RNG k-ε turbulence demonstrate. Nine distinctive design of square rib are considered with relative harshness pitch (P/e = 5-10) and relative unpleasantness stature (e/D = 0.03-0.06). The Reynold number of the stream is shifted from 2500 to 16000. The hydraulic diameter of inner and outer duct of double duct of solar air is varied and an optimum value of hydraulic diameter is found out for maximum thermal efficiency. The effects of relative roughness pitch and relative roughness height on Nusselt number and friction factor have been discussed and the results are compared with the square sectioned rib roughened duct and smooth duct under similar flow conditions to investigate the enhancement in Nusselt number and friction factor. Roughness and flow parameters for artificially roughened solar air heater have been optimized by considering the thermo-hydraulic performance parameter based on constant pumping power requirement. It has been found that the square sectioned transverse continuous rib roughened duct with P/e = 10 and e/D = 0.06 offers the best thermo-hydraulic performance parameter for the investigated range of parameters.