An experimental investigation of the effect of oil on convective heat transfer and pressure drop of a HFC-32/HFC-125 mixture /
The heat transfer coefficients and pressure drops of HCFC-22
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1994.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=741965621&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The heat transfer coefficients and pressure drops of HCFC-22 and a 50% mass mixture of HFC-32/HFC-125 were experimentally measured under flow boiling conditions in a smooth tube. The refrigerants were flowed through an 8 mm diameter smooth tube at mass fluxes of 277, 434, 520 and 700 kg/m2s. Heat fluxes were applied at values of 5100, 7 1 00 and II 000 W/m2. The heat transfer coefficients and pressure drops were measured at refrigerant qualities of 10, 15, 20, 25, 30, 40 and 60 percent. The refrigerants were examined at temperatures near 40C. Oil was added to the HFC-32/HFC-125 mixture in concentrations of 2.6% and 5.4%. Experiments were repeated with the oil laden refrigerant. The heat transfer coefficients for HCFC-22 increased with quality, mass flux and heat flux. The heat transfer coefficients for BFC- 32/HFC-125 often decreased at low qualities and increased with quality at high qualities. . The pressure drop increased with quality and mass flux for both refrigerants. The heat transfer had a minimal effect upon pressure drop. EFC- 32/BFC-125 had a lower pressure drop than HCFC-22 for all conditions. The addition of oil increased the pressure drop. A pressure drop correlation and heat transfer correlation were developed for HFC-32/BFC-125. |
|---|---|
| Item Description: | Vita. "Major Subject: Mechanical Engineering". In title, symbols and numerals are used. |
| Physical Description: | xvii, 201 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |