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Demand for a high thermal performance heat exchanger with good durability in a small packaging space can be very challenging. For the durability testing, the typical thermal cycle test in the lab with the fixed temperature cycles can be very time consuming and costly. In order to shorten the product development time and cost, CAE tools have been explored for the radiator thermal cycle simulation. Due to the nature of the most common failure mode, it is imperative to develop reliable methodologies so that the transient temperature, stress, and corresponding fatigue life for the product can be predicted. This paper focuses on the prediction of the metal temperature during the radiator thermal cycle using computational fluid dynamics (CFD) with conjugate heat transfer. To verify the developed temperature prediction method in CFD, thermal cycle tests were performed for three radiator samples. The test procedure and some of the test results are reviewed.

A multiple reference frame (MRF) model was developed by Gosman [1] for the prediction of flow fields induced by impellers in mixing vessels. The simulation results using this approach agree with the test data reasonably well if certain conditions exist. Many CFD engineers have adopted this approach to simulate the fan performance for automotive powertrain cooling simulations [4]. This paper describes the authors' experience using the MRF model in truck fan simulations. For the fan performance studies with a plate shroud, CFD simulation results with different sizes of rotating zones were compared with the test data. Very good agreement between the CFD simulation and the test data with plate shroud can be achieved if a properly sized rotating zone is selected. For the fan performance studies with a real shroud, a simple piece of plywood was used to mimic the engine blockage and the MRF model with one fixed-size rotation zone was used for the CFD simulation.