This paper analyzes the convective heat transfer enhancement mechanism of latent heat functionally thermal fluid. By using the proposed internal heat source model, the influence of each factor affecting the heat trans...This paper analyzes the convective heat transfer enhancement mechanism of latent heat functionally thermal fluid. By using the proposed internal heat source model, the influence of each factor affecting the heat transfer enhancement of laminar flow in a circular tube with constant heat flux is analyzed. The main influencing factors and the mechanisms of heat transfer enhancement are clarified, and the influences of the main factors on the heat transfer enhancement are quantitatively analyzed. A modified Nusselt number for internal flow is introduced to describe more effectively the degree of heat transfer enhancement for latent functionally thermal fluid.展开更多
The latent heat of the microencapsulated phase change material(MPCM)increases the effective ther-mal capacity of latent functionally thermal fluid.However,researchers found that the heat transfer performance of such f...The latent heat of the microencapsulated phase change material(MPCM)increases the effective ther-mal capacity of latent functionally thermal fluid.However,researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM.For this reason,the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted.The result showed that slurries containing 0.5% TiO2 nanoparticles by mass and 5%―20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced.展开更多
在黄土高原农牧交错带的六道沟流域,采用一维水热传输SHAW(the simultaneous heat and water)模型,对典型植被类型覆盖下2007年4-9月土壤-枯落物-植被冠层间能量传输及分配特征进行模拟研究。结果表明,阳坡油松、柠条和阴坡苜蓿冠层吸...在黄土高原农牧交错带的六道沟流域,采用一维水热传输SHAW(the simultaneous heat and water)模型,对典型植被类型覆盖下2007年4-9月土壤-枯落物-植被冠层间能量传输及分配特征进行模拟研究。结果表明,阳坡油松、柠条和阴坡苜蓿冠层吸收的短波辐射比例最高,而阴坡短花针茅和谷子土壤层表面吸收的短波辐射比例最高。阳坡油松林植被冠层释放的长波有效辐射比例高达91%,土壤层表面的长波有效辐射非常少。其他4种植被则是土壤层表面的长波有效辐射比例最高。能量平衡组成分析表明,阴坡苜蓿和谷子地能量主要消耗于蒸散发的潜热,而阴坡短花针茅地和阳坡柠条、油松林地能量的消耗主要是感热。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.50076020)the Key Projects of Basic Research and Development of China(Grant No.G2000026309)the Excellent Young Faculty Foundation of the Ministry of Education of China.
文摘This paper analyzes the convective heat transfer enhancement mechanism of latent heat functionally thermal fluid. By using the proposed internal heat source model, the influence of each factor affecting the heat transfer enhancement of laminar flow in a circular tube with constant heat flux is analyzed. The main influencing factors and the mechanisms of heat transfer enhancement are clarified, and the influences of the main factors on the heat transfer enhancement are quantitatively analyzed. A modified Nusselt number for internal flow is introduced to describe more effectively the degree of heat transfer enhancement for latent functionally thermal fluid.
基金Supported by the National Natural Science Foundation of China(Grant No. 50076020)
文摘The latent heat of the microencapsulated phase change material(MPCM)increases the effective ther-mal capacity of latent functionally thermal fluid.However,researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM.For this reason,the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted.The result showed that slurries containing 0.5% TiO2 nanoparticles by mass and 5%―20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced.
文摘在黄土高原农牧交错带的六道沟流域,采用一维水热传输SHAW(the simultaneous heat and water)模型,对典型植被类型覆盖下2007年4-9月土壤-枯落物-植被冠层间能量传输及分配特征进行模拟研究。结果表明,阳坡油松、柠条和阴坡苜蓿冠层吸收的短波辐射比例最高,而阴坡短花针茅和谷子土壤层表面吸收的短波辐射比例最高。阳坡油松林植被冠层释放的长波有效辐射比例高达91%,土壤层表面的长波有效辐射非常少。其他4种植被则是土壤层表面的长波有效辐射比例最高。能量平衡组成分析表明,阴坡苜蓿和谷子地能量主要消耗于蒸散发的潜热,而阴坡短花针茅地和阳坡柠条、油松林地能量的消耗主要是感热。
