| Energy and Enviromental Engineering |
|
|
|
|
| Heat transfer characteristics of subcooled flow boiling in one sided heating mini gap |
| FENG Zhao zan, LI Jun ye, LI Wei |
| College of Energy Engineering, Zhejiang University, Hangzhou 310027, China |
|
|
|
Abstract An experimental study of subcooled flow boiling in a one sided heating rectangular channel of high width to height ratio and small length to diameter ratio (W=5.01 mm, H=0.52 mm) was conducted using deionized water. The local heat transfer coefficient, pressure drop and flow pattern of subcooled boiling were measured. The influence of heat flux, mass flux and channel orientation was analyzed with the aid of a high speed camera. Results showed that the flow pattern of vertical upflow boiling was time dependent and governed by isolated bubbly flow. Elongated bubble can be frequently formed at higher heat fluxes either by one nucleated bubble or by bubbles combination. At relatively high mass fluxes (300, 400 kg/(m2·s)), the elongated bubble was pushed out of the heated section immediately owing to larger inertia force. At relatively low mass flux (200 kg/(m2·s)), the elongated bubble tended to expand upstream and finally covered the whole heated section, leading to thin film evaporation beneath the elongated bubble. Heat transfer coefficient was larger than that at higher mass flux due to frequently partial dryout and rewetting. Temperature and pressure drop oscillations with higher amplitude were observed for the horizontally positioned channel. The merged bubbles agglomerate in the heated section for the horizontal orientation under conditions of low heat fluxes, resulting in earlier partial dryout which deteriorates the heat transfer.
|
|
Published: 01 April 2016
|
|
|
单面加热微细窄通道内过冷沸腾的传热特性
以去离子水为工质,对大宽高比、小长径比的单面加热微细窄通道（W=5.01 mm,H=0.52 mm）内的过冷流动沸腾进行实验研究.结合高速摄像,探讨热流密度、质量流速和通道方向对换热系数、压降和流型的影响.结果表明,竖直通道内的沸腾流型随时间变化,主要为孤立泡状流.当热流较高时,孤立汽泡的生长或互相融合可以形成拉长汽泡.在较高流速（300和400 kg/(m2·s)）下,拉长汽泡在惯性力作用下迅速离开加热段；在低流速（200 kg/(m2·s)）下,拉长汽泡向上游扩张,在整个加热段上引发短时薄液膜蒸发过程,并伴随局部干涸和重新润湿的现象,同时换热系数显著高于较高流速下.相对于竖直通道,水平通道内在较低热流下被大量汽泡占据,形成较早的干涸,压降和壁温均出现较大的波动.
|
|
| ［1］ WANG P, MCCLUSKEY P, BAR COHEN A. Two phase liquid cooling for thermal management of IGBT power electronic module ［J］. Journal of Electronic Packaging, 2013, 135(2): 021001.
［2］ TUCKERMAN D B, PEASE R. High performance heat sinking for VLSI ［J］. IEEE Electron Device Letters, 1981, 2(5): 126-129.
［3］ PENG X F, WANG B. Forced convection and flow boiling heat transfer for liquid flowing through microchannels ［J］. International Journal of Heat and Mass Transfer, 1993, 36(14): 3421-3427.
［4］ KANDLIKAR S G. History, advances, and challenges in liquid flow and flow boiling heat transfer in microchannels: a critical review ［J］. Journal of Heat Transfer, 2012, 134(3): 034001.
［5］ LI W, WU Z. A general correlation for evaporative heat transfer in micro/mini channels ［J］. International Journal of Heat And Mass Transfer, 2010, 53(9/10):1778-1787.
［6］ LI W, WU Z. A general criterion for evaporative heat transfer in micro/mini channels ［J］. International Journal of Heat and Mass Transfer, 2010, 53(9/10): 1967-1976.
［7］ ALAM T, LEE P S, YAP C R, et al. A comparative study of flow boiling heat transfer and pressure drop characteristics in microgap and microchannel heat sink and an evaluation of microgap heat sink for hotspot mitigation ［J］. International Journal of Heat and Mass Transfer, 2013, 58(1/2): 335-347.
［8］ BAR COHEN A, SHEEHAN J R, RAHIM E. Two phase thermal transport in microgap channels: theory, experimental results, and predictive relations ［J］. Microgravity Science and Technology, 2012, 24(1): 115.
［9］ SHOJAEIAN M, KOAR A. Pool boiling and flow boiling on micro and nanostructured surfaces ［J］. Experimental Thermal and Fluid Science, 2015, 63: 4573.
［10］ BHAVNANI S, NARAYANAN V, QU W, et al. Boiling augmentation with Micro/Nanostructured surfaces: Current status and research outlook ［J］. Nanoscale and Microscale Thermophysical Engineering, 2014, 18(3): 197-222.
［11］ SAHAR A M, ZDEMIR M R, FAYYADH E M, et al. Single phase flow pressure drop and heat transfer in rectangular metallic microchannels ［J］. Applied Thermal Engineering, 2016, 93: 1324-1336.
［12］ HUANG C, WU C, CHEN Y, et al. The experimental investigation of axial heat conduction effect on the heat transfer analysis in microchannel flow ［J］. International Journal of Heat and Mass Transfer, 2014, 70: 169-173.
［13］ ALAM T, LEE P S, YAP C R, et al. Experimental investigation of local flow boiling heat transfer and pressure drop characteristics in microgap channel ［J］. International Journal of Multiphase Flow, 2012, 42: 164-174.
［14］ KEW P A, CORNWELL K. Correlations for the prediction of boiling heat transfer in small diameter channels ［J］. Applied Thermal Engineering, 1997, 17(8): 705-715.
［15］ STEINKE M E, KANDLIKAR S G. Control and effect of dissolved air in water during flow boiling in microchannels ［J］. International Journal of Heat and Mass Transfer, 2004, 47(8): 1925-1935.
［16］ WHITE F M. Fluid mechanics ［M］. ［S.l.］: McGraw Hill, 2003.
［17］ KANDLIKAR S, GARIMELLA S, LI D, et al. Heat transfer and fluid flow in minichannels and microchannels ［M］. ［S. l.］: Elsevier, 2005.
［18］ KLINE S J, MCCLINTOCK F A. Describing uncertainties in single sample experiments ［J］. Mechanical Engineering, 1953, 75(1): 38.
［19］ SHAH R K. Laminar flow forced convection heat transfer and flow friction in straight and curved ducts: a summary of analytical solutions(Application of laminar flow solutions for heat transfer and flow friction to design of heat exchangers) ［D］. Palo Alto: Stanford University, 1972.
［20］ COLLIER J G, THOME J R. Convective boiling and condensation ［M］. Oxford: Oxford University Press, 1994.
［21］ CHANG W R, CHEN C A, KE J H, et al. Subcooled flow boiling heat transfer and associated bubble characteristics of FC 72 on a heated micro pin finned silicon chip ［J］. International Journal of Heat and Mass Transfer, 2010, 53(23/24): 5605-5621.
［22］ SITAR A, SEDMAK I, GOLOBIC I. Boiling of water and FC 72 in microchannels enhanced with novel features ［J］. International Journal of Heat and Mass Transfer, 2012, 55(23/24): 6446-6457.
［23］ SHIN S, CHOI G, KIM B S, et al. Flow boiling heat transfer on nanowire coated surfaces with highly wetting liquid ［J］. Energy, 2014, 76: 428-435.
［24］ PHAN H T, CANEY N, MARTY P, et al. Flow boiling of water on nanocoated surfaces in a microchannel ［J］. Journal of Heat Transfer, 2012, 134(2): 020901.
［25］ THOME J R. Boiling in microchannels: a review ofexperiment and theory ［J］. International Journal of Heat and Fluid Flow, 2004, 25(2): 128-139.
［26］ LIU Z, WINTERTON R H S. A general correlation for saturated and subcooled flow boiling in tubes and annuli, based on a nucleate pool boiling equation ［J］. International Journal of Heat and Mass Transfer, 1991, 34(11): 2759-2766.
［27］ KANDLIKAR S G, BALASUBRAMANIAN P. An experimental study on the effect of gravitational orientation on flow boiling of water in 1054× 197μm parallel minichannels ［J］. Journal of Heat Transfer, 2005, 127(8): 820-829.
［28］ WANG C, CHANG W, DAI C, et al. Effect of inclination on the convective boiling performance of a microchannel heat sink using HFE 7100 ［J］. Experimental Thermal and Fluid Science, 2012, 36: 143-148.
［29］ LEO H L S L, CHVEZ C A, DO NASCIMENTO F J, et al. An analysis of the effect of the footprint orientation on the thermal hydraulic performance of a microchannels heat sink during flow boiling of R245fa ［J］. Applied Thermal Engineering, 2015, 90:907-926. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
