Experimental and numerical investigation of heat transfer and turbulent characteristics of a novel EGR cooler in diesel engine

摘要

In this study, the flow and heat transfer characteristics of three types of EGR coolers including Semi-spiral EGR cooler (S-Spiral EGR cooler), Full-Spiral EGR cooler (F-Spiral EGR cooler) and Full-Smooth EGR cooler (F-Smooth EGR cooler) were investigated. The fluid and heat transfer properties of the new S-spiral EGR cooler system were studied experimentally and numerically using CFD, but the other two types, F-Spiral EGR cooler and F-Smooth EGR cooler were studied only numerically using CFD. Numerical simulation results showed that an acceptable compatibility exists between the experimental and the numerical results; such that for heat transfer efficiency, the difference between experimental and numerical results was reported to be about 8%, for Nusselt number, the difference between the experimental and numerical results was reported to be 6-8%, and for overall heat transfer coefficient, the difference between the experimental and numerical results was reported to be 9%. The experimental results of the study showed that for the newly built cooling system, S-spiral EGR cooler, the average heat transfer efficiency is 63.2%. The results showed that at a same flow rate, the heat transfer efficiency of S-spiral EGR cooler is more than F-Smooth EGR cooler, but the heat transfer efficiency of F-Spiral EGR cooler is more than the other two, also the pressure drop in F-Spiral EGR cooler is more than semi-Spiral EGR cooler and F-Smooth EGR cooler, therefore the use of the new cooling system (S-spiral EGR cooler) has many benefits, in term of pressure drop and heat transfer efficiency, over the other two types. (C) 2016 Elsevier Ltd. All rights reserved.