Performance of Gaseous Parallel-Flow Micro Heat Exchangers

2006 ◽  
Author(s):  
Y. Asako ◽  
C. Hong ◽  
J. Miwa ◽  
M. Faghri
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Parallel Plate ◽  
Parallel Flow ◽  
Channel Height ◽  
Arbitrary Lagrangian Eulerian ◽  
Flux Variation ◽  
Eulerian Method ◽  
Arbitrary Lagrangian Eulerian Method

Heat exchangers performance of two-stream parallel-flow gas-gas type micro-heat exchangers is investigated numerically. The flow passages of the micro-heat exchangers are parallel-plate channels with heights in the range of 10 to 100 μm and selected lengths of 12.7 and 25.4 mm. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian method. The computations were performed to find the effects of capacity ratio, channel height and length on the heat exchange characteristics of micro heat exchangers. The results are presented in form of temperature contours, bulk temperatures, total temperatures and heat flux variation along the channel. Also, the correlation between the effectiveness and Ntu is discussed.

Performance of Gaseous Counter-Flow Micro Heat Exchangers

2007 ◽  
Author(s):  
J. Miwa ◽  
C. Hong ◽  
Y. Asako ◽  
M. Faghri
Keyword(s):  
Heat Flux ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Parallel Plate ◽  
Channel Height ◽  
Arbitrary Lagrangian Eulerian ◽  
Flux Variation ◽  
Counter Flow ◽  
Eulerian Method ◽  
Arbitrary Lagrangian Eulerian Method

Heat exchangers performance of two-stream counter-flow gas-gas type micro-heat exchangers is investigated numerically. The flow passages of the micro-heat exchangers are parallel-plate channels with heights in the range of 10 to 100 μm and selected lengths of 12.7 and 25.4 mm. The numerical methodology is based on the Arbitrary-Lagrangian-Eulerian method. The computations were performed to find the effects of capacity ratio, channel height and length on the heat exchange characteristics of micro heat exchangers. The results are presented in form of temperature contours, bulk temperatures, total temperatures and heat flux variation along the channel. Also, the correlation between the effectiveness and Ntu is discussed.

Performance of Gas-to-Gas Micro-Heat Exchangers

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
J. Miwa ◽  
Y. Asako ◽  
C. Hong ◽  
M. Faghri
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Temperature Inversion ◽  
Channel Height ◽  
Arbitrary Lagrangian Eulerian ◽  
Flux Variation ◽  
Counter Flow ◽  
Numerical Result ◽  
Arbitrary Lagrangian Eulerian Method

Heat transfer performance of two-stream parallel and counter-flow gas-to-gas micro-heat exchangers are investigated numerically. Flow passages are plane channels with heights in the range of 10–100μm and selected lengths of 12.7mm and 25.4mm. Numerical methodology is based on the arbitrary-Lagrangian-Eulerian method. Computations were performed to find the effects of capacity ratio, channel height, and length on the heat transfer characteristics of micro-heat exchangers. To results are presented in the form of temperature contours, bulk temperatures, total temperatures, and heat flux variation along the channel. It was found that the temperature inversion occurs under certain conditions. Also, the effectiveness and the number of transfer units approach and the estimation of the heat exchange rate were discussed. The range of parameters where the predicted effectiveness agrees with the numerical result were investigated.

Effects of Pressure and Channel Depth on Desorption in Microscale Fractal-Like Branching Heat Exchangers

2007 ◽  
Author(s):  
Mario Apreotesi ◽  
Greg Mouchka ◽  
Keith Davis ◽  
Alex Tulchinsky ◽  
Deborah Pence
Keyword(s):  
Heat Exchange ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Ammonia Solution ◽  
Solution Flow Rate ◽  
Channel Height ◽  
Channel Depth ◽  
Solution Flow ◽  
Flow Network ◽  
Oil Flow

Desorption in micro-scale plate heat exchangers having a branching flow network is investigated as a function of oil flow rate, solution flow rate, manifold pressure and channel depth. The solution is an aqueous-ammonia solution with an inlet concentration held fixed at 30%. Mass flow rate and ammonia mass fraction of the generated vapor stream are characterized as is the heat exchange effectiveness of the various heat exchange desorbers. The effects of operating or exit plenum pressure and channel height on desorption and heat transfer characteristics are considered. Microscale channels are employed for enhanced heat and mass transport. The branching nature of the flow network is employed for flow symmetry and low pressure drop penalties. An operational model is generated to correctly size and efficiently integrate the desorber into an absorption cycle.

Sign in / Sign up

Export Citation Format

Share Document