Development, production and testing of optimised designs of compact heat exchangers containing heat transfer surfaces with implanted vortex generators; VEHE
Among the three vortexes enhanced heat exchanger configurations designed and tested within this project only the fin-tube VEHE design has been immediately fit for production. The net savings of heat transfer area, volume and weight for this design are between 35 and 10 % depending on the Reynolds number or flow velocity in the heat exchanger without VGs considered as reference. This would lead to a mean net cost saving of about 15 to 20%. The plate heat exchanger design b with embossed VGs suggests expecting savings of the same order, as compared to a plain plate heat exchanger. However the manufacture and assembly of embossed plates still provides problem, which led to postpone the manufacture of VEHE design b. The plate heat exchanger, VEHE design c, with secondary fins and punched vortex generators produces much too high flow losses as compared to heat transfer augmentation and is extreme expensive to manufacture. This design has consequently to be left out of further consideration. Software developed within this project allows heat exchanger design for minimum cost operation and allows moreover comparing easily competing heat exchanger designs from the point of view of minimum costs of heat transfer.