Pressure drop of R134a and R1234ze(E) during condensation in horizontal microchannel arrays cooled symmetrically and asymmetrically

2018 ◽  
Vol 96 ◽  
pp. 266-283 ◽  
Author(s):  
Ji Wang ◽  
Jun Ming Li
Keyword(s):  
Pressure Drop ◽  
Microchannel Arrays

An Experimental Investigation of Pressure Drop in Expanding Microchannel Arrays

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Mark J. Miner ◽  
Patrick E. Phelan ◽  
Brent A. Odom ◽  
Carlos A. Ortiz
Keyword(s):  
Heat Flux ◽  
Pressure Drop ◽  
Flow Boiling ◽  
Spectral Response ◽  
Low Frequency ◽  
Pressure Effects ◽  
Pressure Drops ◽  
Microchannel Arrays ◽  
R 134A ◽  
Expanding Channel

The pressure effects of expanding the cross section of microchannels along the direction of flow are investigated across four rates of channel expansion in the flow boiling of R-134a. Prior investigation by the authors detailed the fabrication of four copper microchannel arrays and the pumped-loop apparatus developed to facilitate interchange of the microchannel specimens, allowing consistency across experiments. Significant beneficial pressure effects are observed to result from the expansion, including reduction by half of the pumping cost per flow rate at critical heat flux. The improvements are seen with small expansions, and greater expansion yields diminishing returns. The high pressure drops associated with microchannel evaporators are effectively reduced by expanding channel geometry, and the low-frequency system spectral response indicates that expanding channel arrays typically carry less energy in oscillations up to 2.5 Hz, suggesting amelioration of oscillatory instabilities. Results are discussed in light of a comparative force analysis, with the balance of these forces linked to the observed behavior of the pressure drop and heat flux relationship.

PREDICTION OF PRESSURE DROP THROUGH BAFFLE INJECTOR

2014 ◽  
Vol 24 (3) ◽  
pp. 273-280
Author(s):  
Kyubok Ahn ◽  
Hwan-Seok Choi
Keyword(s):  
Pressure Drop

Flow and pressure drop in annular ducts with one rotating surface

2017 ◽  
Author(s):  
C. Y. Nakashima ◽  
S. de Oliveira Jr. ◽  
E. F. Caetano
Keyword(s):  
Pressure Drop ◽  
Rotating Surface
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