ENGR5003 Lecture 6 worked example 3 (slides 16-18)
A refrigerant (R134a) enters a capillary tube of a refrigerator as a saturated liquid at 0.8 MPa and is throttled to a pressure of 0.12 MPa. Determine the temperature of the initial state and the temperature and dryness fraction of the final state.
R134a saturation data (pressure table):
| p (kPa) | T (C) | (m3/kg) | (m3/kg) | (kJ/kg) | (kJ/kg) | (kJ/kg) |
|---|---|---|---|---|---|---|
| 120 | -22.3 | 0.0007324 | 0.1621 | 22.5 | 214.5 | 237.0 |
| 800 | 31.3 | 0.0008459 | 0.0256 | 95.5 | 171.8 | 267.3 |
Formulas you may need
- SFEE with and negligible KE, PE: (throttling is isenthalpic) (on the formula sheet as the SFEE)
- Dryness fraction: , so (on the formula sheet)