EXPERIMENTAL AND NUMERICAL STUDIES ON INTERACTION OF RADIATION WITH OTHER MODES OF HEAT TRANSFER

Abstract To investigate the application of ribbed cross-flow coolant channels with film hole effusion and the effects of the internal cooling configuration on film cooling, experimental and numerical studies are conducted on the effect of the relative position of the film holes and different orientation ribs on the film cooling performance. Three cases of the relative position of the film holes and different orientation ribs (post-rib, centered, and pre-rib) in two ribbed cross-flow channels (135° and 45° orientation ribs) are investigated. The film cooling performances are measured under three blowing ratios by the transient liquid crystal measurement technique. A RANS simulation with the realizable k-ε turbulence model and enhanced wall treatment is performed. The results show that the cooling effectiveness and the downstream heat transfer coefficient for the 135° rib are basically the same in the three position cases, and the differences between the local effectiveness average values for the three are no more than 0.04. The differences between the heat transfer coefficients are no more than 0.1. The “pre-rib” and “centered” cases are studied for the 45° rib, and the position of the structures has little effect on the film cooling performance. In the different position cases, the outlet velocity distribution of the film holes, the jet pattern and the discharge coefficient are consistent with the variation in the cross flow. The related research previously published by the authors showed that the inclination of the ribs with respect to the holes affects the film cooling performance. This study reveals that the relative positions of the ribs and holes have little effect on the film cooling performance. This paper expands and improves the study of the effect of the internal cooling configuration on film cooling and makes a significant contribution to the design and industrial application of the internal cooling channel of a turbine blade.

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The Research of Energy Conversion and Heat Transfer in the Ceramic Foams of Solar Energy Converter

Volume 4: Energy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy, Parts A and B ◽

10.1115/imece2011-63013 ◽

2011 ◽

Author(s):

Yangbo Deng ◽

Fengmin Su ◽

Chunji Yan

Keyword(s):

Heat Transfer ◽

Numerical Model ◽

Solar Radiation ◽

Solar Energy ◽

Numerical Models ◽

Air Flow ◽

Energy Converter ◽

Ceramic Foams ◽

Numerical Studies ◽

Flow Through

The solar energy converter in Concentrated Solar Power (CSP) system, applies the solid frame structure of the ceramic foams to receive the concentrated solar radiation, convert it into thermal energy, and heat the air flow through the ceramic foams by convection heat transfer. In this paper, first, the pressure drops in the studied ceramic foams were measured under all kinds of flow condition. Based on the experimental results, an empirical numerical model was built for the air flow through ceramic foams. Second, a 3-D numerical model was built, for the receiving and conversion of the solar energy in the ceramic foams of the solar energy converter. Third, applying two aforementioned numerical models, the numerical studies of the thermal performance were carried out, for the solar energy converter filled with the ceramic foams, and results show that the structure parameters of the ceramic foams, the effective reflective area and the solar radiation intensity of the solar concentrator, have direct impacts on the absorptivity and conversion efficiency of the solar energy in the solar energy converter. And the results of the numerical studies are found to be in reasonable agreement with the experimental measurements. This paper will provide a reference for the design and manufacture of the solar energy converter with the ceramic foams.

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Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Energies ◽

10.3390/en14206458 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6458

Author(s):

Liaqat Hussain ◽

Muhammad Mahabat Khan ◽

Manzar Masud ◽

Fawad Ahmed ◽

Zabdur Rehman ◽

...

Keyword(s):

Heat Transfer ◽

Phase Change Materials ◽

Jet Impingement ◽

Target Surface ◽

Industrial Applications ◽

Heat Transfer Augmentation ◽

Numerical Studies ◽

Single Jet ◽

Jet Nozzle ◽

Future Work

Jet impingement is considered to be an effective technique to enhance the heat transfer rate, and it finds many applications in the scientific and industrial horizons. The objective of this paper is to summarize heat transfer enhancement through different jet impingement methods and provide a platform for identifying the scope for future work. This study reviews various experimental and numerical studies of jet impingement methods for thermal-hydraulic improvement of heat transfer surfaces. The jet impingement methods considered in the present work include shapes of the target surface, the jet/nozzle–target surface distance, extended jet holes, nanofluids, and the use of phase change materials (PCMs). The present work also includes both single-jet and multiple-jet impingement studies for different industrial applications.

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Numerical studies of temperature and thermoelastic stress due to local heat transfer coefficient transients

Nuclear Engineering and Design ◽

10.1016/0029-5493(70)90048-8 ◽

1970 ◽

Vol 12 (3) ◽

pp. 313-325 ◽

Cited By ~ 3

Author(s):

J.J. Thompson ◽

Z.J. Holy ◽

P. Chen

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Thermoelastic Stress ◽

Local Heat Transfer ◽

Local Heat ◽

Local Heat Transfer Coefficient ◽

Numerical Studies

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Positioning Effect on Free Convection with an Elliptical Plate Placed in a Circular Enclosure

Advanced Science Engineering and Medicine ◽

10.1166/asem.2020.2668 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1054-1062

Author(s):

Parth Patpatiya ◽

Soumya ◽

Bhavya Shaan ◽

Bhavana Yadav

Keyword(s):

Heat Transfer ◽

Aspect Ratio ◽

The Body ◽

Elliptical Plate ◽

Numerical Studies ◽

First Case ◽

Varied Temperature ◽

Laminar Natural Convection ◽

The Given ◽

Plate System

In this analysis we have examined the process of the steady state laminar natural convection around heated elliptical plate with Rayleigh number 10^6 positioned inside a circular enclosure. The purpose of the numerical analysis is to analyze the behavior of isotherms, streamlines and heat transfer rate in enclosure plate system due to the variation in the position of elliptical plate (r/D =0.00, 0.05, and 0.2) and aspect ratio, where the given diameter of the enclosure is D and r is the distance between the centre of elliptical plate and centre of circle. Elliptical plate is inclined at different angles and results are summed up in relative manner. There are two cases, in first case aspect ratio a/D and b/D is varied and D is kept constant, whereas in second case aspect ratio a/D and b/D is kept constant and D is varied. Temperature difference between the enclosure and the inner body (i.e., temperature of inner body is kept high as compared to the enclosure) is maintained. Two dimensional study is followed by considering air as a fluid in enclosure. The effects of the Heat Transfer and Flow of Fluid are analyzed by the streamlines and isotherms plotted for the body placed inside enclosure. Value of local Nusselt number (Nu) is also plotted along the wall of elliptical plate and along the surface of the circular enclosure. For every aspect ratio isotherms and streamlines had been plotted. This work has been validated with various other numerical studies and was in good conciliation.

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