|Support type:||Scholarships in Brazil - Doctorate|
|Effective date (Start):||May 01, 2011|
|Effective date (End):||April 30, 2015|
|Field of knowledge:||Engineering - Mechanical Engineering - Transport Phenomena|
|Principal Investigator:||Gherhardt Ribatski|
|Grantee:||Daniel Felipe Sempértegui Tapia|
|Home Institution:||Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil|
In general,this doctoral research project deals with the analysis of the effect of the channel geometry on the two-phase flow pattern, heat transfer coefficient and the pressure drop during convective boiling inside channels of an equivalent diameter close to 1 mm. Experiments will be performed for refrigerants R134a and R245fa for triangular and rectangular channels with aspect ratios equal to 4, 2, 1 and ½. Experimental results determined with the implementation of this research proposal will be compared with results for circular cross section obtained by the group during the doctoral thesis of Tibiriça (Grand number 2007/53950-5 from FAPESP). Experimental techniques and data analysis procedures already developed by the group will be used in order to investigate the effect of the channel cross section geometry on the two-phase flow pattern, heat transfer coefficient and pressure drop. An extensive database will be obtained in an experimental setup in the Department of Mechanical Engineering, EESC-USP, which is available and operational. The objective method for identifying two-phase flow patterns developed during the dissertation of the applicant (Grand number 2008/56930-8 from FAPESP) and described in Sempértegui Ribatski (2010) will be used. This will allows the development of pressure losses and heat transfer coefficient models which include the predominant physical mechanisms of each flow regime. Aspects related to the effects of aspect ratio of rectangular channels, effects of the edges of the rectangular channels and triangular channels, will be studied through a careful visual analysis of images obtained by a high speed camera (8000 frames/s).