Thermal Fluid Flow Transport Phenomena in a Channel Containing Slot-Perforated Flat Plates

2007 ◽  
Author(s):  
Shuichi Torii ◽  
Wen Jei Yang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Plate Thickness ◽  
Transfer Performance ◽  
Flat Plates ◽  
Lower Region ◽  
Blockage Factor

A numerical study is performed to investigate unsteady, two-dimensional, incompressible laminar flow over both sides of a slot-perforated flat surface in a pulsating channel flow. Enhances is placed on the effects of the pulsating Strouhal number, the Reynolds number Re, the blockage factor, i.e., the ratio of plate thickness, d, to channel width, W, on the heat transfer performance and the velocity and thermal fields. It is found from the study that: (i) when the fluid stream is pulsated, the alternating change in the fluid flow disturbs the thermal boundary layer formed along the plate and induces mixing of the upper and lower streams of the plate downstream from the slot, resulting in an amplification of heat-transfer performance; (ii) heat transfer performance at the rear plate is induced with Re; (iii) by contrast, heat transfer performance is attenuated with an increase in the blockage factor, whose effect becomes larger in the lower region of the Reynolds number; and (iv) heat transfer performance is intensified with an increase in fSr, whose effect becomes minor in the lower region of the Reynolds number.

Effect of Blockage Factor on Thermal-Fluid Flow Transport Phenomenon Over Slot-Perforated Flat Surface in Channel

2003 ◽  
Author(s):  
Shuichi Torii ◽  
Shinzaburo Umeda ◽  
Wen-Jei Yang
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Performance ◽  
Flat Surface ◽  
Plate Thickness ◽  
Transfer Performance ◽  
Thermal Fields ◽  
Blockage Factor ◽  
Exchange Resins ◽  
Thermal Fluid Flow

A numerical and experimental study is performed to investigate unsteady, two-dimensional, incompressible laminar flow over both sides of a slot-perforated flat surface, which is placed in a channel. Enhances is placed on the effect of the blockage factor, i.e., the ratio of plate thickness, δ, to channel width, W, on the heat transfer performance and the velocity and thermal fields. It is found from the study that: (i) when the slot width is increased, the alternating change in the fluid flow disturbs the thermal boundary layer formed along the plate and induces mixing of the upper and lower streams of the plate downstream from the slot, resulting in an amplification of heat transfer performance; (ii) heat transfer performance at the rear plate is induced with an increase in d/δ and Re; and (iii) by contrast, heat transfer performance is attenuated with an increase in the blockage factor, whose effect becomes larger in the lower region of the Reynolds number. These results are confirmed by the flow visualization using ion-exchange resins.

Simulation of Thermal Fluid Flow Transport in a Channel Containing Slot-Perforated Flat Plates

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang
Keyword(s):  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Plate Thickness ◽  
Flat Plates ◽  
Thermal Fields ◽  
Blockage Factor ◽  
Flow Transport ◽  
Thermal Fluid Flow

A numerical study is performed to investigate unsteady, two-dimensional, incompressible laminar flow over both sides of a slot-perforated flat surface in a pulsating channel flow. Consideration is given to the effects of the pulsating Strouhal number fSr, the Reynolds number Re, and the blockage factor, i.e., the ratio of plate thickness, δ, to channel width, W, on the heat-transfer performance and the velocity and thermal fields. It is found from the study that (i) time-averaged Nusselt number at the rear plate is amplified with Re, (ii) in contrast, the corresponding performance is attenuated with an increase in the blockage factor, whose effect becomes larger in the lower region of the Reynolds number, i.e., Re=100, and (iii) enhancement of the Nusselt number causes an increase in fSr, whose effect becomes minor near in the region of Re=100.

Experimental and Numerical Studies of Fluid Flow Confined in Microchannel

2016 ◽  
Author(s):  
Yan Wang ◽  
Xiang Ling
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Friction Factor ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
High Heat Flux ◽  
Transfer Performance ◽  
Parallel Microchannels

The heat transfer performance of fluid flowing in a microchannel was experimentally studied, to meet the requirement of extremely high heat flux removal of microelectronic devices. There were 10 parallel microchannels with rectangular cross-section in the stainless steel plate, which was covered by a glass plate to observe the fluid flowing behavior, and another heating plate made of aluminum alloy was positioned behind the microchannel. Single phase heat transfer and fluid flow downstream the microchannel experiments were conducted with both deionized water and ethanol. Besides experiments, numerical models were also set up to make a comparison with experimental results. It is found that the pressure drop increases rapidly with enlarging Reynolds number (200), especially for ethanol. With comparison, the flow resistance of pure water is smaller than ethanol. Results also show that the friction factor decreases with Reynolds number smaller than the critical value, while increases the velocity, the friction factor would like to keep little changed. We also find that the water friction factors obtained by CFD simulations in parallel microchannels are much larger than experiment results. With heat flux added to the fluid, the heat transfer performance can be enhanced with larger Re number and the temperature rise could be weaken. Compared against ethanol, water performed much better for heat removal. However, with intensive heat flux, both water and ethanol couldn’t meet the requirement and the temperature at outlet would increase remarkably, extremely for ethanol. These findings would be helpful for thermal management design and optimization.

A Numerical Study of the Flow and Heat Transfer in the Pin Fin-Dimple Channels With Various Dimple Depths

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Yu Rao ◽  
Yamin Xu ◽  
Chaoyi Wan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Convective Heat Transfer ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Transfer Performance ◽  
Number Range ◽  
Flow Friction ◽  
Pin Fin ◽  
Flow And Heat Transfer

A numerical study was conducted to investigate the effects of dimple depth on the flow and heat transfer characteristics in a pin fin-dimple channel, where dimples are located spanwisely between the pin fins. The study aimed at promoting the understanding of the underlying convective heat transfer mechanisms in the pin fin-dimple channels and improving the cooling design for the gas turbine components. The flow structure, friction factor, and heat transfer performance of the pin fin-dimple channels with various dimple depths have been obtained and compared with each other for the Reynolds number range of 8200–80,800. The study showed that, compared to the pin fin channel, the pin fin-dimple channels have further improved convective heat transfer performance, and the pin fin-dimple channel with deeper dimples shows relatively higher Nusselt number values. The study still showed a dimple depth-dependent flow friction performance for the pin fin-dimple channels compared to the pin fin channel, and the pin fin-dimple channel with shallower dimples shows relatively lower friction factors over the studied Reynolds number range. Furthermore, the computations showed the detailed characteristics in the distribution of the velocity and turbulence level in the flow, which revealed the underlying mechanisms for the heat transfer enhancement and flow friction reduction phenomenon in the pin fin-dimple channels.

Numerical Flow Visualization and Thermal Transport Phenomena Over a Slot-Perforated Flat Surface in Pulsating Channel Flow

2002 ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Channel Flow ◽  
Heat Transfer Performance ◽  
Theoretical Study ◽  
Flat Surface ◽  
Plate Thickness ◽  
Transfer Performance ◽  
Thermal Fields ◽  
Thermal Fluid Flow

A theoretical study is performed to investigate unsteady, two-dimensional, incompressible thermal-fluid flow over both sides of a slot-perforated flat surface, which is placed in a pulsating channel flow. The roles of both the pulsating Strouhal number and the ratio of the channel width to the plate thickness, W/δ, on the velocity and thermal fields are disclosed. It is found from the study that: (i) when the channel stream is pulsated, the alternating change in the fluid flow disturbs the thermal boundary layer formed along the plate and induces mixing of the upper and lower streams of the plate downstream from the slot, resulting in an amplification of heat transfer performance, and (ii) heat transfer performance at the plate is attenuated with a decrease in W/δ.

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