Calculation and discussion of adiabatic throttling coefficient for moist air

Based on the modified PR equation(MPR equation) and the compression factor equation, changing the calculation of the Joule-Thomson coefficient into the calculation of partial derivative of the compression factor to temperature in the constant pressure condition, deduces a calculation method of the adiabatic throttling coefficient for moist air. In verifying this method, firstly calculates the compression factor of saturated moist air and compares it with the data from related literatures; secondly calculates the Joule-Thomson factors of the oxygen gas in different pressures and temperatures condition and compares them with the calculation values by an empirical formula based on experimental data, with the results showing that the method has higher accuracy; finally analyses the influence of the temperature, pressure and humidity ratio on the adiabatic throttling coefficient of moist air, and compares the calculation result by MPR equation and that by PR equation.