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Heat transfer plays an important role in the conceptual and detail design of cooling system of modern DI engine and has considerable influence over their operational performance and durability. The consequential demand for higher possible heat transfer rates has lead to the very promising concept of providing for a controlled transition from pure single-phase convection to subcooled boiling flow in some high thermal load regions. In order to achieve controlled boiling over a wide range of operation conditions, the detailed flow and heat transfer analysis is essential. CFD simulation incorporating the boiling model is an effective approach for such analysis. Four different boiling heat transfer models are proposed and developed within CFD framework, two based on Division Description Method (DDM), and another two based on Superposition Method (SM).

The combination of 1D and 3D fluid flow models is achieved using a co-simulation methodology. This realizes that the internal flow in a component simulated in 3D is incorporated into a network (system) containing components represented in 1D. This methodology gives the details of the internal flow while conserving overall mass flow in the system, thus eliminating uncertainties in boundary conditions prescribed in the 3D model and reducing the overall simulation time. This paper shows numerical results for internal flow of water flow circuit of engine cooling system and availability and current problem of 1D/3D co-simulation method are discussed.

A windshield defroster has an important roll of clearing up fogged window glasses of a vehicle by blowing out warm air. In simulations parameters that affect the defogging time are the velocity, humidity and temperature of the flow from a defroster nozzle. However, individually varying all the parameters and investigating their effects will lead to many computing cases and long runtime. An approach that can considerably reduce calculation time is proposed. The approach is dictated by two key-steps: 1) First, steady-state velocity distributions for several different defroster flow rates are calculated; 2) Secondly, based on the pre-calculated velocity fields, the defogging time is estimated. This approach is compared to the conventional method that always couples all the parameters in transient calculations.

Recently, many CFD analyses which assist mechanical designing have been carried out in every aspects of automotive engineering. While many CFD tools have been developed for easies of use and advances in CFD analyses tools continue, instances of effective design using these tools are not well discussed in the literature. This paper discusses a CFD analysis system, SC/Tetra, is equipped with an automatic hybrid mesh generator, a high-speed flow solver and a state of the art postprocessor. In SC/Tetra, the flow solver is built on a node-based finite-volume discretization method to achieve both high-speed computation and small memory consumption. The advancing-front method is applied to the automatic mesh generator. These features of efficient computation are desired to achieve shorter design times. Discussions are made after performing sample computations of a torque converter for an automobile, which presents difficulties for efficient CFD analysis.