scholarly journals Numerical investigation of surface roughness effects on heat transfer in a turbine cascade

2019 ◽  
Author(s):  
Arunprasath Subramanian ◽  
Andrea Gamannossi ◽  
Lorenzo Mazzei ◽  
Antonio Andreini
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Numerical Investigation ◽  
Turbine Cascade ◽  
Roughness Effects

Numerical investigation of the surface roughness effects on the subsonic flow around a circular cone-cylinder

2020 ◽  
Vol 107 ◽  
pp. 106271
Author(s):  
Noureddine Saidi ◽  
Mahfoudh Cerdoun ◽  
Smail Khalfallah ◽  
Toufik Belmrabet
Keyword(s):  
Surface Roughness ◽  
Numerical Investigation ◽  
Subsonic Flow ◽  
Circular Cone ◽  
Roughness Effects

scholarly journals Heat Transfer Enhancement by Shot Peening of Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 584
Author(s):  
Pramote Koowattanasuchat ◽  
Numpon Mahayotsanun ◽  
Sedthawatt Sucharitpwatskul ◽  
Sasawat Mahabunphachai ◽  
Kuniaki Dohda
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Process Parameters ◽  
Shot Peening ◽  
Cfd Simulation ◽  
Cost Effective ◽  
Transfer Coefficients ◽  
Roughness Effects ◽  
Heat Transfer Efficiency

In heat exchange applications, the heat transfer efficiency could be improved by surface modifications. Shot peening was one of the cost-effective methods to provide different surface roughness. The objectives of this study were (1) to investigate the influences of the surface roughness on the heat transfer performance and (2) to understand how the shot peening process parameters affect the surface roughness. The considered specimens were 316L stainless steel hollow tubes having smooth and rough surfaces. The computational fluid dynamics (CFD) simulation was used to observe the surface roughness effects. The CFD results showed that the convective heat transfer coefficients had linear relationships with the peak surface roughness (Rz). Finite element (FE) simulation was used to determine the effects of the shot peening process parameters. The FE results showed that the surface roughness was increased at higher sandblasting speeds and sand diameters.

Characterization and Laboratory Simulation of Turbine Airfoil Surface Roughness and Associated Heat Transfer

1998 ◽  
Vol 120 (2) ◽  
pp. 337-342 ◽  
Author(s):  
D. G. Bogard ◽  
D. L. Schmidt ◽  
M. Tabbita
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Free Stream ◽  
Laboratory Simulation ◽  
Roughness Effects ◽  
Average Roughness ◽  
Airfoil Surface ◽  
Free Stream Turbulence

The physical characteristics of surface roughness observed on first-stage high-pressure turbine vanes that had been in service for a long period were investigated in this study. Profilometry measurements were utilized to provide details of the surface roughness formed by deposits of foreign materials on different parts of the turbine vane. Typical measures of surface roughness such as centerline average roughness values were shown to be inadequate for characterizing roughness effects. Using a roughness shape parameter originally derived from regular roughness arrays, the turbine airfoil roughness was characterized in terms of equivalent sand-grain roughness in order to develop an appropriate simulation of the surface for laboratory experiments. Two rough surface test plates were designed and fabricated. These test plates were evaluated experimentally to quantify the heat transfer rate for flow conditions similar to that which occurs on the turbine airfoil. Although the roughness levels on the two test plates were different by a factor of two, both surfaces caused similar 50 percent increases in heat transfer rates relative to a smooth surface. The effects of high free-stream turbulence, with turbulence levels from 10 to 17 percent, were also investigated. Combined free-stream turbulence and surface roughness effects were found to be additive, resulting in as much as a 100 percent increase in heat transfer rate.

Surface Roughness Effects on Heat Transfer in Microscale Single Phase Flow: A Critical Review

2008 ◽  
Author(s):  
Perry L. Young ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Critical Review ◽  
Heat Dissipation ◽  
Transport Phenomena ◽  
Volume Ratio ◽  
Heat Transfer Characteristics ◽  
Roughness Effects ◽  
Transfer Characteristics ◽  
Microscale Transport

There has been increasing interest in research regarding microscale transport phenomena over the past decade. The increased surface area to volume ratio of a microchannel presents enhanced heat transfer characteristics when compared to conventional channels. For this reason, there has been heightened interest in the use of microchannels to meet the high heat dissipation demands of electronics. The fundamental understanding of microscale transport phenomena is an increasingly important area of research, and one area where such understanding is lacking is the effects of surface roughness on transport phenomena. There is very little published literature discussing the effects of surface roughness on the heat transfer characteristics of microchannels, and what literature exists exhibits discrepancies between experimental results. This paper serves as a critical review of literature from 2000 to the present, both experimental and theoretical, involving surface roughness effects on heat transfer in microscale transport phenomena.

Numerical Research of Roughness Effects on Flow and Heat Transfer Characteristics in Flat Microchannels

2009 ◽  
Author(s):  
Heming Yun ◽  
Baoming Chen ◽  
Binjian Chen
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Reynolds Number ◽  
Conjugate Heat Transfer ◽  
Entrance Length ◽  
Heat Transfer Characteristics ◽  
Roughness Effects ◽  
Relative Roughness ◽  
Flow And Heat Transfer ◽  
Numerical Research

Roughness effects on flow and heat transfer in flat microchannels has been numerically simulated by using CFD with fluid-solid conjugate heat transfer techniques, the surface roughness has been modeled through a series triangular toothed roughness cells. In this paper, the influence for roughness on the entrance length of flow and heat transfer has been emphasized, the influence for relative roughness on transitional Reynolds number has been also analyzed at the same time.

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