Abstract

The equivalent outer diameter of the four tubes (1EHT-1, 1EHT-2, 4LB and a smooth tube) was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318K, over a mass flow range of 150-450 kgm−2s−1, with inlet and outlet vapor qualities of 0.8 and 0.2, respectively. Evaporation tests were performed at a saturation temperature of 279K, over a mass flow range of 150-380 kgm−2s−1, with inlet and outlet vapor qualities of 0.2 and 0.8, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model, and present an accurate method to predict the frictional pressure drop of the tested tubes. For condensation data of 1EHT-1, 1EHT-2 and the smooth tube, the correlations of Muller-Steinhagen and Heck and Friedel were found to present good consistency, with the Mean Absolute Relative Deviation (MARD) being smaller than 13%, while that of the other 3 correlations based on the homogeneous flow model were found to be over 29.5%. For the evaporation data of all the tubes tested, the Friedel correlation was found to provide the most accurate prediction with an average MARD of 12.0%, followed by the Muller-Steinhagen and Heck, and the homogeneous- flow model based correlations.

This content is only available via PDF.

Article PDF first page preview

Article PDF first page preview
You do not currently have access to this content.