A summary of some of the objectives and conclusions reached in this project are:
• A literature search on post dryout heat transfer for pure refrigerants and for refrigerant-oil mixtures was performed and a comprehensive review written (Chapters 9,10 and 11);
• The correct thermodynamic definition of the heat transfer coefficient for evaporation of refrigerant-oil mixtures was presented and men used in the project, i.e. defining the heat transfer coefficient using the local bubble point temperature Tbub of the refrigerant-oil mixture rather than with the saturation temperature of the pure refrigerant Tsat incorrectly used in prior studies (Chapter 3);
• A new generalized approach, that is simple to implement, was developed for predicting bubble point temperatures of refrigerant-oil mixtures for miscible oils mat can be applied to any refrigerant-oil combination and is accurate over the local oil concentration range from 0-50 wt.% oil range confronted in direct-expansion evaporators with 0-5 wt.% oil in their refrigerant charge (Chapter 4);
• A new thermodynamic method for preparation of temperature-enthalpy-vapor quality (T-h-x) curves for refrigerant-oil mixtures for general application was developed and validated against test data (Chapters 5 and 6), including a simple expression for calculating local oil concentrations as a function of vapor quality;
• New, accurate thermodynamic methods for preparation of temperature-enthalpy-vapor quality (T-h-x) curves for the refrigerant blend R-407C and R-407C/oil mixtures were developed developed for thermal design of evaporators and for the present experimental tests, and was validated against measured test data (Chapter 12).
Product Details
- Published:
- 1997
- Number of Pages:
- 268
- File Size:
- 1 file , 8.4 MB
- Product Code(s):
- D-RP-800
