In the present paper the pressure drop characteristics of a 1.4 mm hydraulic diameter multiport minichannel tube during adiabatic two-phase flow of R134a and R410A are presented. The tube consists of eleven parallel rectangular channels. Although much experimental research has been devoted to investigate the pressure drop characteristics of low pressure refrigerants inside multiport minichannels in the last years, very little information is available on high pressure refrigerants, such as R410A, whose behaviour is very different from R134a. The experimental runs are carried out at mass velocities ranging from 400 to 1000 kg/(m2 s) for R134a and from 600 to 1400 kg/(m2 s) for R410A, over the entire vapour quality range. The frictional pressure gradient is obtained from the saturation temperature drop measurement. The experimental frictional pressure drop data is compared against models available in the literature for prediction of frictional pressure gradient in channels. The comparison of calculated vs. experimental values shows that the R134a frictional pressure gradient in the multiport minichannel test tube can be fairly well predicted by available correlations, while no model can guarantee a satisfactory agreement with the R410A experimental data.
Measurement of pressure gradient during two-phase flow inside multi-port mini-channels
CAVALLINI, ALBERTO;DEL COL, DAVIDE;DORETTI, LUCA;MATKOVIC, MARKO;ROSSETTO, LUISA;ZILIO, CLAUDIO
2004
Abstract
In the present paper the pressure drop characteristics of a 1.4 mm hydraulic diameter multiport minichannel tube during adiabatic two-phase flow of R134a and R410A are presented. The tube consists of eleven parallel rectangular channels. Although much experimental research has been devoted to investigate the pressure drop characteristics of low pressure refrigerants inside multiport minichannels in the last years, very little information is available on high pressure refrigerants, such as R410A, whose behaviour is very different from R134a. The experimental runs are carried out at mass velocities ranging from 400 to 1000 kg/(m2 s) for R134a and from 600 to 1400 kg/(m2 s) for R410A, over the entire vapour quality range. The frictional pressure gradient is obtained from the saturation temperature drop measurement. The experimental frictional pressure drop data is compared against models available in the literature for prediction of frictional pressure gradient in channels. The comparison of calculated vs. experimental values shows that the R134a frictional pressure gradient in the multiport minichannel test tube can be fairly well predicted by available correlations, while no model can guarantee a satisfactory agreement with the R410A experimental data.Pubblicazioni consigliate
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