池沸腾临界热流密度及临界波长的实验研究
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摘要
分别在光滑及波形结构的铜表面上对水和乙醇进行饱和池沸腾实验,观测了临界热流密度(CHF)下临界波长的变化趋势,并分析了表面结构对沸腾传热系数及CHF的影响。实验验证了光滑表面上,临界波长随工质的不同而变化,继而影响CHF,其实验值与经典的临界波长及临界热流密度理论一致。而粗糙表面上的乙醇沸腾实验进一步发现,波形结构可以减小临界波长,从而有效提高CHF,其影响规律与相关文献的理论模型较为符合。
Experiments of saturated pool boiling of water and ethanol on smooth and wave-shaped cooper surfaces were performed respectively.The changes of the critical wavelength for the occurrence of Critical Heat Flux(CHF)were observed and the effects of surface structures on boiling heat transfer coefficient and CHF were analyzed.The results show that on a smooth surface the critical wavelength varies with working fluids and may affects the CHF.The experimental data is found in agreement with the classic model of critical wavelength and CHF.In addition,pool boiling experiments of saturated ethanol show wave-shaped structure can reduce the critical wavelength,therefore the CHF can be enhanced effectively.The influence rules show good agreement with relevant literature latest model.
Experiments of saturated pool boiling of water and ethanol on smooth and wave-shaped cooper surfaces were performed respectively.The changes of the critical wavelength for the occurrence of Critical Heat Flux(CHF)were observed and the effects of surface structures on boiling heat transfer coefficient and CHF were analyzed.The results show that on a smooth surface the critical wavelength varies with working fluids and may affects the CHF.The experimental data is found in agreement with the classic model of critical wavelength and CHF.In addition,pool boiling experiments of saturated ethanol show wave-shaped structure can reduce the critical wavelength,therefore the CHF can be enhanced effectively.The influence rules show good agreement with relevant literature latest model.
引文
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[2]KANDLIKAR S G.A theoretical model to predict pool boiling CHF incorporating effects of contact angle and orientation[J].J of Heat Transfer,2001,123(6):1071-1079.
[3]BETZ A R,XU J,QIU H,et al.Do surfaces with mixed hydrophilic and hydrophobic areas enhance pool boiling[J].Appl Phys Lett,2010,97(14):141909.
[4]KIM H D,KIM M H.Effect of nanoparticle deposition on capillary wicking that influences the critical heat flux in nanofluids[J].Appl Phys Lett,2007,91(1):014104.
[5]AHN H S,JO H J,KANG S,et al.Effect of liquid spreading due to nano/microstructures on the critical heat flux during pool boiling[J].Appl Phys Lett,2011,98(7):071908.
[6]ZUBER N.Hydrodynamic Aspects of Boiling Heat Transfer[D].Las Angeles,CA:Univ.of California,1959.
[7]POLEZHEAV Y V,KOVALEV S A.Modelling heat transfer with boiling on porous structures[J].Therm Eng,1990,37(12):617-620.
[8]QUANG X,DONG L,CHENG P.A CHF model for saturated pool boiling on a heated surface with micro/nano-scale structures[J].Int J of Heat and Mass Transfer,2014,76:452-458.
[9]COOKE D,KANDLIKA S G.Pool boiling heat transfer and bubble dynamics over plain and enhanced microchannels[J].J of Heat Transfer,2011,133(5):052902.
[10]杨世铭,陶文铨.数值传热学[M].第三版.北京:高等教育出版社,1998.
[11]LAMB H.Hydrodynamics[M].New York:Dover Pub.,1957.