利用NCEP/NCAR 1979—2013年的再分析资料,研究了冬季阿留申低压低频变化的环流特征,探讨了阿留申低压低频变化形成和维持的相关天气尺度瞬变强迫机制。冬季阿留申低压的低频变化在850 h Pa环流场上表现为北太平洋海盆区一个异常气旋/...利用NCEP/NCAR 1979—2013年的再分析资料,研究了冬季阿留申低压低频变化的环流特征,探讨了阿留申低压低频变化形成和维持的相关天气尺度瞬变强迫机制。冬季阿留申低压的低频变化在850 h Pa环流场上表现为北太平洋海盆区一个异常气旋/异常反气旋在局地强弱变化的过程,即阿留申低压在低频尺度上先异常增强/减弱随后逐渐恢复正常态的演变过程;850 h Pa上大气温度低频变化表现为低频冷中心在西北太平洋建立并逐渐东移的过程。对天气尺度瞬变扰动活动及其强迫的异常进行分析表明,北太平洋海盆区上空的瞬变动力强迫在阿留申低压异常增强的时期为负异常,有利于阿留申低压低频变化异常空间型的形成和维持。由瞬变热力强迫异常引起的温度倾向异常场表现为北太平洋中部以40°N为界南正—北负的空间分布,其南部正异常在一定程度上抑制和削弱了低频冷中心向南的扩张。展开更多
High-temperature Phase Change Material (PCM) is used as a thermal storage medium of a heat-pipe receiver in an advanced solar dynamic system.With both void cavity and natural convection considered,thermal performance ...High-temperature Phase Change Material (PCM) is used as a thermal storage medium of a heat-pipe receiver in an advanced solar dynamic system.With both void cavity and natural convection considered,thermal performance of the heat-pipe receiver is numerically analyzed under gravity.The results indicate that the PCM contained in the integrated heat pipe performs an averaging function of heat loadings.The thermal performance of the heat-pipe receiver is stable and reliable.When a heating cycle is stable,the temperature fluctuations both on heat-pipe wall and in PCM canister remain less than 13 K throughout a sunlight and eclipse cycle.The utility of PCM is essentially improved.The maximum melting ratio of PCM is 92%.Under gravity,PCM melts more quickly with the effect of natural convection.Natural convection accelerates the process of phase changes.Numerical results are compared with the experimental results concerned.The accuracy of numerical model under gravity is verified.The experiment for the PCM canister on the ground can be well prepared with our numerical simulation.展开更多
文摘利用NCEP/NCAR 1979—2013年的再分析资料,研究了冬季阿留申低压低频变化的环流特征,探讨了阿留申低压低频变化形成和维持的相关天气尺度瞬变强迫机制。冬季阿留申低压的低频变化在850 h Pa环流场上表现为北太平洋海盆区一个异常气旋/异常反气旋在局地强弱变化的过程,即阿留申低压在低频尺度上先异常增强/减弱随后逐渐恢复正常态的演变过程;850 h Pa上大气温度低频变化表现为低频冷中心在西北太平洋建立并逐渐东移的过程。对天气尺度瞬变扰动活动及其强迫的异常进行分析表明,北太平洋海盆区上空的瞬变动力强迫在阿留申低压异常增强的时期为负异常,有利于阿留申低压低频变化异常空间型的形成和维持。由瞬变热力强迫异常引起的温度倾向异常场表现为北太平洋中部以40°N为界南正—北负的空间分布,其南部正异常在一定程度上抑制和削弱了低频冷中心向南的扩张。
文摘High-temperature Phase Change Material (PCM) is used as a thermal storage medium of a heat-pipe receiver in an advanced solar dynamic system.With both void cavity and natural convection considered,thermal performance of the heat-pipe receiver is numerically analyzed under gravity.The results indicate that the PCM contained in the integrated heat pipe performs an averaging function of heat loadings.The thermal performance of the heat-pipe receiver is stable and reliable.When a heating cycle is stable,the temperature fluctuations both on heat-pipe wall and in PCM canister remain less than 13 K throughout a sunlight and eclipse cycle.The utility of PCM is essentially improved.The maximum melting ratio of PCM is 92%.Under gravity,PCM melts more quickly with the effect of natural convection.Natural convection accelerates the process of phase changes.Numerical results are compared with the experimental results concerned.The accuracy of numerical model under gravity is verified.The experiment for the PCM canister on the ground can be well prepared with our numerical simulation.
