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| Author(s): |
Alex Alberto Silva Huerta
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2000-05-12 |
| Examining board members: |
Otavio de Mattos Silvares;
Jose Maria Saiz Jabardo;
José Roberto Simões Moreira;
Roberto de Aguiar Peixoto;
Miriam Rocchi Tavares
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| Advisor: | Otavio de Mattos Silvares |
| Abstract | |
A numerical and experimental model was developed to investigate the effects of the oil on the performance of capillary tubes considering a separated flow model. The numerical simulation integrates the one dimensional governing equations for thefluid flow (continuity, momentum and energy), using a step by step numerical method. The numerical model was used to illustrate that the separated flow model differs of homogeneous flow model mainly at the outlet region of capillary tube and thepresence of oil produces a reduction in the flow mass rate. The experimental investigation evaluated the influence of oil on the performance of capillary tubes with the refrigerants R-134a and R-600a. Initial studies about the metastable flowwere realized for both pure refrigerant and refrigerant-oil mixtures. The experimental results showed changes in the mass flow rate with the addition of oil for different condensation pressures and different sub-cooling degree. The flow massrate for the R-600a (isobutane) is approximately 30% lower than for R-134a. (AU) | |