Performance of Gaseous Counter-Flow Micro Heat Exchangers

Author(s):  
J. Miwa ◽  
C. Hong ◽  
Y. Asako ◽  
M. Faghri

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.

Author(s):  
Y. Asako ◽  
C. Hong ◽  
J. Miwa ◽  
M. Faghri

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.


2009 ◽  
Vol 131 (5) ◽  
Author(s):  
J. Miwa ◽  
Y. Asako ◽  
C. Hong ◽  
M. Faghri

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.


2018 ◽  
Vol 7 (2.20) ◽  
pp. 250
Author(s):  
Banoth Mohan ◽  
V Ashok Kumar

A device may be a device worked for the sensible heat exchange beginning with one liquid then onto the attendant, paying very little reference to whether or not the liquids square measure isolates by a powerful divider in order that they ne'er mix, or the liquids square measure particularly in touch. reliably get some data concerning in device progression is creating to form productive, traditionalist and stinting heat exchangers, where for the duration of the planet. Strengthening the function for this alteration wants associate degree association. In most up-to-date 5 years coaxial tube heat exchangers use unnatural convection to cut down the temperature of a operating liquid whereas raising the temperature of the cooling medium. The motivation driving this paper is to utilize ANSYS FLUENT12.1 programming and hand counts to interrupt down the temperature drops as a neighborhood of each straight speed and delta temperature and the way each modification with the opposite. every gleam money dealer show was worked in steps and examined in transit till the purpose that the instant that each parallel stream and counter stream heat money dealer models were created. The outcomes were thought of between every model and among parallel and counter stream with fouled funneling. Turbulent stream was conjointly impecunious down amidst the distinction within the shine exchangers to choose its impact on heat exchange. whereas clearly the fouled heat money dealer had a lower execution and during this manner cooled the operating liquid less, the execution of the counter heat money dealer out of the blue of the parallel heat money dealer.


Author(s):  
Mario Apreotesi ◽  
Greg Mouchka ◽  
Keith Davis ◽  
Alex Tulchinsky ◽  
Deborah Pence

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.


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