【摘 要】
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This paper investigates the optimization conditions of the parameters of a reciprocating spray coating processes to improve the uniformity of absorptivity and emissivity distributions on a selective a
【机 构】
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Department of Aeronautics and Astronautics,National Cheng Kung University,Tainan 701,Taiwan
【出 处】
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13th International Conference on Liquid Atomization and Spra
论文部分内容阅读
This paper investigates the optimization conditions of the parameters of a reciprocating spray coating processes to improve the uniformity of absorptivity and emissivity distributions on a selective absorbing film.The characteristics of the absorbing film play a key role in determining the collection efficiency of solar thermal energy.The absorptivity(α)and emissivity(ε)of the thickness sensitive spectrally selective(TSSS)are very sensitive to the thickness of the film; both increase as its thickness is increased.According to the results of the literature,the solar heater with a TSSS film of thickness of approximately 3 ± 1 μm could achieve the highest temperature under the same sun radiation conditions.This research used the Taguchi method with four control factors include(1)pressure of gas/liquid(Pa/Pl),(2)injection height,(3)ratio of concentration of paint and solvent,and(4)moving speed of the nozzle.The quality of the spray coating processes is measured by absorptivity and emissivity of the TSSS in this research.The optimal combination of L9(36)orthogonal array is gas/liquid pressure of 2.5/0.8 2/kgf cm,28cm for height,0.5 for the ratio of concentration of paint and solvent,and 29.57 cm/s for moving speed of nozzle.It turns out that the quality characteristics for the ratio of absorptivity and emissivity is increased from 1.165 to 1.368,and the S/N ratio of absorptivity is decreased from 60.01 dB to 39.31 dB,as comparing the confirmation and original tests.It show that reduce the thickness of the film and upgrade the uniformity successfully.
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