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| Author(s): |
Rogerio Rodrigues Junior
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: | 1999-12-22 |
| Examining board members: |
Jurandir Itizo Yanagihara;
Guenther Carlos Krieger Filho;
Julio Romano Meneghini;
Eugênio Spanó Rosa;
Edson Luiz Zaparoli
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| Advisor: | Jurandir Itizo Yanagihara |
| Abstract | |
This work presents a numerical investigation of the influence of vortex generators (VG) on the heat transfer enhancement of fin-tube compact heat exchangers with two rows of tubes in staggered and in-line arrangements. Heat exchanger configurations with several longitudinal and transverse tube pitches were studied. The overall dimensions and the operating condition were based on typical values used for heat exchangers of domestic air conditioning systems. The position and angle of attack of vortex generators (VG) were varied, but other geometric parameters were fixed according to the best results in the literature. The numerical model, based on the finite volume method, used a boundary-fitted coordinate system because of its geometrical complexity. Laminar steady-state simulations were carried out to Re=300 and the conjugate heat transfer mode was considered. Results obtained for models with smooth fins show how the mean heat transfer coefficient and the pressure drop are affected by the longitudinal and transverse tube pitches, becoming the first systematic study on this subject. Results with VG show that, when it is positioned in the first tube row, it has a great importance in the global heat transfer enhancement. New values of position and angle of attack of VG, based on phenomenologic studies, were proposed, and models with these parameters present higher heat transfer augmentation rate than models with the default literature values. (AU) | |