Experimental check of certain methods of determining P-V-T relations of N₂-O₂ mixtures in the gas and vapor regions

Conclusions

• 1. Comparison is made of experimentally developed P-V-T relations for N₂-O₂ mixtures at 100–350°K and pressures up to 6 MPa with the results obtained through two semiempirical methods of calculation.

• 2. Each of these semiempirical methods gives a good representation of the P-V-T relations over the interval from τ ⩾ 1.2 to τ ⩽ 0.9 (τ is the ratio of the temperature to the pseudo-critical temperature) over the entire range of pressures and compositions. The deviation from the measured values was no more than the maximum experimental error of 0.5%. As a rule, values obtained by method I were low, and those obtained by method II high.

• 3. The error of each of the semiempirical methods were no more than 1% over the 1.1⩽ τ < 1.2 range.

• 4. Method II gave more exact values than method I over the 1.01 < τ < 1.1 and 0.90 < τ < 0.99 intervals, and with a maximum error of 5%, but the error of calculation fell off sharply in moving away from the critical region and the saturated vapor curve.

• 5. In the critical region itself (0.99 < τ < 1.01) 0.9 <π < 1.1), the error of each method was of the order of 20−40%.