Vipertex 2EHT Results Published in the Journal of International Communications in Heat and Mass Transfer Journal
Results from a study that evaluated the performance of 2EHT tubes has just been published in a heat transfer journal.
Title:Experimental study on condensation and evaporation ﬂow inside horizontal three dimensional enhanced tubes
Journal title: International Communications in Heat and Mass Transfer Journal. Volume 80, Page 30-40, 2017.
Experimental investigations of tube side condensation and evaporation in two 3-D enhanced heat transfer (2EHT) tubes were compared to the performance of a smooth surface copper tube. The equivalent outer diameter of all the tubes was 12.7 mm with an inner diameter of 11.5 mm. Both the inner and outer surfaces of the 2EHT tubes are enhanced by longitudinal grooves with a background pattern made up by an array of dimples/embossments. Experimental runs were performed using R410A as the working ﬂuid, over the quality range of 0.2–0.9. For evaporation, the heat transfer coefﬁcient ratio (compares the heat transfer coefﬁcient of the enhanced tube to that of a smooth tube) of the 2EHT tubes is 1.11–1.43 (with an enhanced surface area ratio of 1.03) for mass ﬂux rate that ranges from 80 to 200 kg/m s. For condensation, the heat transfer coefﬁcient ratio range is 1.1– 1.16 (with an enhanced surface area ratio of 1.03) for mass ﬂux that ranges from 80 to 260 kg/m s. Frictional pressure drop values for the 2EHT tubes are very similar to each other. Heat transfer enhancement in the 2EHT tubes is mainly due to the dimples and grooves in the inner surface that create an increased surface area and interfacial turbulence; producing higher heat ﬂux from wall to working ﬂuid, ﬂow separation, and secondary ﬂows. A comparison was performed to evaluate the enhancement effect of the 2EHT tubes using a deﬁned performance factor and this indicates that the 2EHT tubes provides a better heat transfer coefﬁcient under evaporation conditions.