Problem 53HP

Saturated vapor R-410a at 60°C changes volume at constant temperature. Find the new pressure, and quality if saturated, if the volume doubles. Repeat the problem for the case where the volume is reduced to half of the original volume.

Solution 53 HP

Step 1 of 2

We have to the pressure and quality of Saturated vapor R-410a at 60°C when the volume changes to double.

The specific volume of saturated vapour of R-410a at 60o C can be found from the Table.5.1

in the book.

0.00497 m3/kg kPa (saturated)

The specific volume of saturated vapour of R-140a, if the volume doubles at constant temperature is

Since the mass is constant, specific volume also doubles when the volume doubles.

= 0.00994 m3/kg superheated vapour

The pressure of the R-140 at 60oC and with specific volume 0.00994 m3/kg can be found by interpolating between 2000 kPa and 3000 kPa from the Table B.5.2 in the book.

m3/kg at 2000 kPa and m3/kg at 3000 kPa

= 2000+(1000)(0.8)

= 2800 kPa

The quality is 1 as it is in vapour state only.

Therefore, the new pressure and quality are 2800 kPa and 1.