Natural Convection/Radiation Heat Transfer From Highly Populated Pin Fin Arrays

1985 ◽  
Vol 107 (1) ◽  
pp. 190-197 ◽  
Author(s):  
E. M. Sparrow ◽  
S. B. Vemuri
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Radiation Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Radiation Heat ◽  
Pin Fin ◽  
Pin Fins ◽  
Pin Fin Arrays ◽  
Fin Length ◽  
Combined Mode

Experiments were performed to determine the combined-mode natural convection/radiation heat transfer characteristics of highly populated arrays of rodlike cylindrical fins (i.e., pin fins). The fins were oriented with their axes horizontal and were attached to a vertical heated baseplate. The investigated parameters included the number of fins in the array, the fin length and diameter, the baseplate-to-ambient temperature difference, and the presence or absence of adjacent shrouding surfaces. Finning was found to be highly enhancing (up to a sixfold increase in heat transfer), and even the longest fins were highly efficient. When the number of fins was increased for fixed values of the other parameters, the heat transfer increased at first, attained a maximum, and then decreased. Arrays having different diameter fins yielded about the same performance when the surface area of the fin-baseplate assembly was held fixed. Shrouding surfaces positioned close to the array decreased the rate of heat transfer. Calculations showed that the contribution of radiation was substantial and was greatest for more populous arrays, for longer fins, and at small temperature differences.

scholarly journals Influence of Varying Pressure on Natural Convection and Radiation Heat Transfer in an Enclosure

PAMM ◽  
2005 ◽  
Vol 5 (1) ◽  
pp. 575-576 ◽  
Author(s):  
Jan Langebach ◽  
Stephan Senin ◽  
Christian Karcher
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Radiation Heat Transfer ◽  
Radiation Heat

2D Natural Convection and Radiation Heat Transfer Simulations of a PWR Fuel Assembly Within a Constant Temperature Support Structure

2006 ◽  
Author(s):  
Pablo E. Araya Go´mez ◽  
Miles Greiner
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Fuel Assembly ◽  
Heat Generation ◽  
Temperature Difference ◽  
Wall Temperature ◽  
Radiation Heat Transfer ◽  
Radiation Heat ◽  
Fuel Rods ◽  
Water Reactor

Two-dimensional simulations of steady natural convection and radiation heat transfer for a 14×14 pressurized water reactor (PWR) spent nuclear fuel assembly within a square basket tube of a typical transport package were conducted using a commercial computational fluid dynamics package. The assembly is composed of 176 heat generating fuel rods and 5 larger guide tubes. The maximum cladding temperature was determined for a range of assembly heat generation rates and uniform basket wall temperatures, with both helium and nitrogen backfill gases. The results are compared with those from earlier simulations of a 7×7 boiling water reactor (BWR). Natural convection/radiation simulations exhibited measurably lower cladding temperatures only when nitrogen is the backfill gas and the wall temperature is below 100°C. The reduction in temperature is larger for the PWR assembly than it was for the BWR. For nitrogen backfill, a ten percent increase in the cladding emissivity (whose value is not well characterized) causes a 4.7% reduction in the maximum cladding to wall temperature difference in the PWR, compared to 4.3% in the BWR at a basket wall temperature of 400°C. Helium backfill exhibits reductions of 2.8% and 3.1% for PWR and BWR respectively. Simulations were performed in which each guide tube was replaced with four heat generating fuel rods, to give a homogeneous array. They show that the maximum cladding to wall temperature difference versus total heat generation within the assembly is not sensitive to this geometric variation.

Row Removal Heat Transfer Study for Pin Fin Arrays

2014 ◽  
Author(s):  
Kathryn L. Kirsch ◽  
Jason K. Ostanek ◽  
Karen A. Thole ◽  
Eleanor Kaufman
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
High Reynolds Number ◽  
Pin Fin ◽  
Heat Transfer Augmentation ◽  
Aspect Ratios ◽  
Pin Fins ◽  
High Reynolds ◽  
Pin Fin Arrays ◽  
Transfer Study

Arrays of variably-spaced pin fins are used as a conventional means to conduct and convect heat from internal turbine surfaces. The most common pin shape for this purpose is a circular cylinder. Literature has shown that beyond the first few rows of pin fins, the heat transfer augmentation in the array levels off and slightly decreases. This paper provides experimental results from two studies seeking to understand the effects of gaps in pin spacing (row removals) and alternative pin geometries placed in these gaps. The alternative pin geometries included large cylindrical pins and oblong pins with different aspect ratios. Results from the row removal study at high Reynolds number showed that when rows four through eight were removed, the flow returned to a fully-developed channel flow in the gap between pin rows. When larger alternative geometries replaced the fourth row, heat transfer increased further downstream into the array.

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