scholarly journals Heat Transfer Enhancement of Perforated Square Pin-Fin Array in a Rectangular Duct

2017 ◽  
Vol V (IX) ◽  
pp. 1826-1832
Author(s):  
C. Mageswaran
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Rectangular Duct ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Pin Fin Array

Heat Transfer Enhancement of Internal Cooling Passage With Triangular and Semi-Circular Shaped Pin-Fin Arrays

2012 ◽  
Author(s):  
Sin Chien Siw ◽  
Minking K. Chyu ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Internal Cooling ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Pin Fins ◽  
Cooling Passage ◽  
Internal Cooling Passage ◽  
Pin Fin Array ◽  
Pin Fin Arrays

A systematic experimental study has been conducted to explore the heat transfer behavior of triangular and semicircular shaped pin-fin arrays as compared to the circular shaped pin-fin array, that serve as a baseline case. The main advantage of using triangular and semi-circular shaped pin-fin arrays will results in reduced component weight and potentially increases in heat transfer performance. Three staggered arrays with different inter-pin spacing in both transverse and longitudinal are explored in order to determine the optimal configuration for these three dimensional element. Both semi-circular and circular shaped pin-fin arrays are based on typical inter-pin spacing of 2.5 times the pin diameter. The channel geometry (width, W = 76.2mm, height, E = 25.4mm) simulates an internal cooling passage of wide aspect ratio (3:1) in a gas turbine airfoil. All pin-fin elements are fully bridged from one endwall to the opposite endwall. The Reynolds number, based on the hydraulic diameter of the unobstructed cross-section and the mean bulk velocity, ranges from 10,000 to 25,000. The heat transfer measurement employs a hybrid liquid crystal imaging technique, which combined one-dimensional, transient conduction model and lumped heat-capacitance model. Triangular pin-fin arrays produce the highest heat transfer enhancement, while the semi-circular pin-fin array yields the lowest heat transfer enhancement. Sharp edges at each triangular pin-fin generated more wake and turbulence, resulting in more mixing, induces greater heat transfer enhancement by approximately 10%–20% as compared to the typical pin-fins of circular cross-section. More uniform heat transfer is also observed on the endwall and neighboring pin-fins in all triangular shaped pin-fin arrays. However, triangular pin-fin arrays give the highest pressure loss due to the largest induced form drag among all cases, while circular pin-fin array exhibits the lowest pressure loss.

scholarly journals Efficiency Improvement of Miniaturized Heat Exchangers

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Iris Gerken ◽  
Thomas Wetzel ◽  
Jürgen J. Brandner
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Assessment Method ◽  
Flow Path ◽  
Transfer Enhancement ◽  
Pressure Losses ◽  
Pin Fin ◽  
Additional Pressure ◽  
The Impact

Micro heat exchangers have been revealed to be efficient devices for improved heat transfer due to short heat transfer distances and increased surface-to-volume ratios. Further augmentation of the heat transfer behaviour within microstructured devices can be achieved with heat transfer enhancement techniques, and more precisely for this study, with passive enhancement techniques. Pin fin geometries influence the flow path and, therefore, were chosen as the option for further improvement of the heat transfer performance. The augmentation of heat transfer with micro heat exchangers was performed with the consideration of an improved heat transfer behaviour, and with additional pressure losses due to the change of flow path (pin fin geometries). To capture the impact of the heat transfer, as well as the impact of additional pressure losses, an assessment method should be considered. The overall exergy loss method can be applied to micro heat exchangers, and serves as a simple assessment for characterization. Experimental investigations with micro heat exchanger structures were performed to evaluate the assessment method and its importance. The heat transfer enhancement was experimentally investigated with microstructured pin fin geometries to understand the impact on pressure loss behaviour with air.

Experimental Investigation Into the Influence of Varying Stagger on the Performance of a Pin-Fin Array

2008 ◽  
Author(s):  
W. D. Allan ◽  
S. A. Andrews ◽  
M. LaViolette
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Pressure Loss ◽  
Reynolds Numbers ◽  
Design Criterion ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Line Array ◽  
Array Performance ◽  
Pin Fin Array

A six row pin-fin array was constructed with a spanwise spacing of 2.5 diameters, streamwise spacing of 1.5 diameters and a height to diameter ratio of 1. The streamwise stagger of alternate rows was continuously varied from fully in-line to fully staggered. Tests were carried out at Reynolds numbers of 2.7 × 104 and 2.3 × 104, corresponding to maximum velocities, in the low subsonic range, of 21 m/s and 18 m/s respectively. These results showed that the array averaged heat transfer was greatest from a fully staggered array and had a minimum at a stagger slightly greater than fully in-line. However, with increasing stagger, the array-averaged friction factor grew at a greater rate than the heat transfer. The ensuing analysis of the total array performance, considering both the magnitude of heat transfer and the losses within the array, showed that the fully in-line array had the highest ratio of heat transfer enhancement to friction factor enhancement. Therefore, if pressure loss was a design criterion, the fully in-line array was preferable. However, if pressure loss was not a constraint, then the staggered array was preferable.

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