A new throttling flow calorimeter has been incorporated into the recycle facility of the Thermal Properties Laboratory. Energy is added to the expanding gas while it flows through a stainless steel capillary tubing from an insulated resistance wire located inside the entire length of the capillary. The calorimeter is designed to operate at pressures up to 2,000 lb./sq.in.abs. in the temperature range from −240 to +250°F.
Data on the isothermal effect of pressure on enthalpy for a mixture containing 5 mole % propane in methane are presented and compared with data from the literature.