The Structure Optimization Numerical Exehanger Simulation Of The Night Sky Radiation Heat

Through the night sky radiation to reduce the temperature of the ground object is asimple and effective and energy-saving way of passive cooling. Based on existing researchresults of the night sky radiation, the structure of heat exchanger has been optimized, ourresearch group study out the optimum height and the economic velocity, the temperature ofthe fin heat exchanger and pressure drop are analyzed and compared with no finned heatexchanger. Studied the fin height, fin spacing, imported mass flow rate and the influence ofoutdoor velocity to the night sky radiation heat exchanger and gotten the followingconclusions:(1)Import and export temperature difference and pressure drop of the night skyradiation heat exchanger decreases with the increasing of the height of heat exchanger, Thecold gathering power of heat exchanger increases with the increasing of import flowvelocity, The length of heat exchanger is10m, with the width400mm,when the height is50mm, cooling power collection reachs maximum.(2)The pipe air temperature of two kinds of heat exchanger models graduallydecreases with the increasing of the flow distance, the pressure drop of the heat exchangerincreases with the increasing of flow distance. Under the same conditions, the coldgathering power and the pressure drop of finned heat exchanger are both lager than nofinned heat exchanger.(3)When the rib spacing fixed, import and export temperature difference in heatexchanger and pressure drop with the increasing of rib high increases gradually; When ribheight fixed, with the increase of the rib spacing, the outlet temperature of the heatexchanger shows the tendency of increase with the decrease of the first, and the pressuredrop decreases.(4)Analyzing the temperature and pressure drop between the rib of5mm height,50mm rib spacing of finned heat exchanger and no finned heat exchanger.With the increasing of Imported mass flow, outlet temperature of the heat exchangerincreases, imports velocity effects on the exit temperature increases graduallyweakened,while import velocity on the influence of finned heat exchanger outlet temperature rising is larger than no finned heat exchanger. When the inlet velocity from1m/s to6m/s, thecooling efficiency of Finned heat exchanger increases by24.4%,13.3%and13.3%respectively,10.0%,11.8%,13.3%. The pressure drop are3.33,3.38,3.37,3.37,3.47,3.61times than the no finned heat exchanger.(5)The outdoor velocity on the influence of temperature rise rate difference is so littlebetween two kinds of heat exchanger, the outlet temperature of the two kinds of heatexchanger is small growth trends.