基于新型高温高压喷雾闪蒸实验台,以水为工质,研究初始条件和运行条件对闪蒸蒸发特性的影响。首次将液体初始温度提高至100℃以上,将闪蒸罐运行压力保持为正压,并使用具有独特双S形叶片的涡旋实心锥喷嘴,将液体向上或向下喷入闪蒸罐。...基于新型高温高压喷雾闪蒸实验台,以水为工质,研究初始条件和运行条件对闪蒸蒸发特性的影响。首次将液体初始温度提高至100℃以上,将闪蒸罐运行压力保持为正压,并使用具有独特双S形叶片的涡旋实心锥喷嘴,将液体向上或向下喷入闪蒸罐。实验过程中液体初始温度为135-150℃,闪蒸压力分别为121、126、131、136、141、146 k Pa,液体过热度为30-46℃。实验结果表明,闪蒸蒸汽流量随初始温度的提高而增大,随闪蒸压力的提高而减小。液体向下喷射比向上喷射产汽量更高,蒸汽带水更少。闪蒸效率随过热度呈线性增长,在大量实验数据基础上拟合出二者之间的经验公式。实验结果为高温高压喷雾闪蒸的工业应用提供借鉴。展开更多
Spay cooling is a complicated flow and heat transfer process affected by multi-factors among which the environmental pressure is extremely important. However the influence of pressure is not investigated sufficiently,...Spay cooling is a complicated flow and heat transfer process affected by multi-factors among which the environmental pressure is extremely important. However the influence of pressure is not investigated sufficiently, especially the reduced pressure. In the present study, spray cooling under low initial environmental partial pressures and vapor partial pressures with R21 are investigated with a closed spray and condensation system. To study the influence of initial environmental partial pressure, different amounts of nitrogen are inflated into the vacuum flash chamber, while the vapor partial pressure is kept constant. To study the influence of vapor partial pressure, a cascade refrigerator is used to condense the vapor with different condensation temperatures so that the vapor partial pressure can be maintained or adjusted, while the initial environmental partial pressure is kept constant.The experimental results show that the spray cooling power increases monotonically with the increasing spray flow rate in the experimental range, while the cooling efficiency decreases with the increasing spray flow rate. The spray cooling power and cooling efficiency vary with the initial environmental partial pressure or the vapor partial pressure non-monotonously, which indicates there is an optimal pressure for the heat transfer performance. Besides, the mechanism of the non-monotonous variation trend is discussed based on the key aspects including flash evaporation, convection and boiling. Especially, the boiling heat transfer curve is applied to explain the trend.展开更多
文摘基于新型高温高压喷雾闪蒸实验台,以水为工质,研究初始条件和运行条件对闪蒸蒸发特性的影响。首次将液体初始温度提高至100℃以上,将闪蒸罐运行压力保持为正压,并使用具有独特双S形叶片的涡旋实心锥喷嘴,将液体向上或向下喷入闪蒸罐。实验过程中液体初始温度为135-150℃,闪蒸压力分别为121、126、131、136、141、146 k Pa,液体过热度为30-46℃。实验结果表明,闪蒸蒸汽流量随初始温度的提高而增大,随闪蒸压力的提高而减小。液体向下喷射比向上喷射产汽量更高,蒸汽带水更少。闪蒸效率随过热度呈线性增长,在大量实验数据基础上拟合出二者之间的经验公式。实验结果为高温高压喷雾闪蒸的工业应用提供借鉴。
基金supported by the National Natural Science Foundation of China(Grant No.51376101)the National Science Fund for Creative Research Groups(Grant No.51621062)
文摘Spay cooling is a complicated flow and heat transfer process affected by multi-factors among which the environmental pressure is extremely important. However the influence of pressure is not investigated sufficiently, especially the reduced pressure. In the present study, spray cooling under low initial environmental partial pressures and vapor partial pressures with R21 are investigated with a closed spray and condensation system. To study the influence of initial environmental partial pressure, different amounts of nitrogen are inflated into the vacuum flash chamber, while the vapor partial pressure is kept constant. To study the influence of vapor partial pressure, a cascade refrigerator is used to condense the vapor with different condensation temperatures so that the vapor partial pressure can be maintained or adjusted, while the initial environmental partial pressure is kept constant.The experimental results show that the spray cooling power increases monotonically with the increasing spray flow rate in the experimental range, while the cooling efficiency decreases with the increasing spray flow rate. The spray cooling power and cooling efficiency vary with the initial environmental partial pressure or the vapor partial pressure non-monotonously, which indicates there is an optimal pressure for the heat transfer performance. Besides, the mechanism of the non-monotonous variation trend is discussed based on the key aspects including flash evaporation, convection and boiling. Especially, the boiling heat transfer curve is applied to explain the trend.
