The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The puriti...The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The purities of HFC152a and HFC32 are all 99.95%.The flow apparatus for measuring heat capacities of liquid phase compounds and their mixtures under the pressure up to 12 MPa,and at temperatures from 26OK to 47OK was built by the authors.展开更多
Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures fr...Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures from 150 K to 480 K, respectively. Equations for Helmholtz energy, Gibbs energy, internal energy, enthalpy, entropy, isochoric heatcapacity, isobaric heat capacity, speed of sound, and second virial coefficient of HFC-32 arepresented. Independent equations are also included for vapor pressure and saturated liquiddensity as function of temperature.展开更多
根据ASTME681-04及ANSI/ASHRAE Standard 34-2007标准,建立了一套全自动可燃性气体爆炸极限实验系统.该系统实际配气比例与设定比例的误差不超过±0.1%,配气比例的不确定度小于0.5%.对几种常见制冷剂的爆炸极限进行了测试,验证了系...根据ASTME681-04及ANSI/ASHRAE Standard 34-2007标准,建立了一套全自动可燃性气体爆炸极限实验系统.该系统实际配气比例与设定比例的误差不超过±0.1%,配气比例的不确定度小于0.5%.对几种常见制冷剂的爆炸极限进行了测试,验证了系统的准确性.对二甲醚/HFC125混合气体的爆炸极限进行了实验研究,结果表明,加入HFC125后二甲醚的可燃性范围减小,当HFC125与二甲醚的体积比为4.6时达到临界抑爆点,但HFC125含量较低时对二甲醚的阻燃作用不明显.该测试结果为将二甲醚作为一种环保型制冷剂进行推广应用提供了安全参考.展开更多
The paper reports the measurements of the thermal conductivity of gaseous HFC32 over the temperature range 254.51K to 341.76K near the saturation line. The thermal conductivities were measured in a transient hot-wire ...The paper reports the measurements of the thermal conductivity of gaseous HFC32 over the temperature range 254.51K to 341.76K near the saturation line. The thermal conductivities were measured in a transient hot-wire instrument employing two anodized tantalum wires as the heat source with an uncertainty of 1%. The resuilts were correlated as a function of temperature for engineering use.展开更多
文摘The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The purities of HFC152a and HFC32 are all 99.95%.The flow apparatus for measuring heat capacities of liquid phase compounds and their mixtures under the pressure up to 12 MPa,and at temperatures from 26OK to 47OK was built by the authors.
文摘Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures from 150 K to 480 K, respectively. Equations for Helmholtz energy, Gibbs energy, internal energy, enthalpy, entropy, isochoric heatcapacity, isobaric heat capacity, speed of sound, and second virial coefficient of HFC-32 arepresented. Independent equations are also included for vapor pressure and saturated liquiddensity as function of temperature.
文摘根据ASTME681-04及ANSI/ASHRAE Standard 34-2007标准,建立了一套全自动可燃性气体爆炸极限实验系统.该系统实际配气比例与设定比例的误差不超过±0.1%,配气比例的不确定度小于0.5%.对几种常见制冷剂的爆炸极限进行了测试,验证了系统的准确性.对二甲醚/HFC125混合气体的爆炸极限进行了实验研究,结果表明,加入HFC125后二甲醚的可燃性范围减小,当HFC125与二甲醚的体积比为4.6时达到临界抑爆点,但HFC125含量较低时对二甲醚的阻燃作用不明显.该测试结果为将二甲醚作为一种环保型制冷剂进行推广应用提供了安全参考.
文摘The paper reports the measurements of the thermal conductivity of gaseous HFC32 over the temperature range 254.51K to 341.76K near the saturation line. The thermal conductivities were measured in a transient hot-wire instrument employing two anodized tantalum wires as the heat source with an uncertainty of 1%. The resuilts were correlated as a function of temperature for engineering use.
