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Using conventional solvers, the simulation of a complex and large system such as the automotive paint ovens can be quite time consuming - of the order of a several weeks or even months. A reduced order computational model of the oven that can predict thermal distribution quicker is useful in performing optimization studies and in directing finer design changes to the oven and the car body. This research focuses on the development of such a lumped capacitance thermal model (defined here in as the reduced order model: ROM) for predicting the heat of curing of an object that is inside an industrial oven. Essentially, the heat transfer modes are computed through a set of linear ordinary differential equations, by conceptualising the the physical object is conceptualised as a series of inter-connecting nodes that are linked by thermal resistors.

Aerodynamic simulation using commercial CFD (Computational Fluid Dynamics) codes is now an integral part of the vehicle design process. Aerodynamic prediction and vehicle development program runs in parallel. This requires a good agreement between experimental measurements and CFD prediction of aerodynamic behavior of a vehicle. The comparison between experimental and simulation results show differences, as it may not be possible to replicate effect of all the wind tunnel parameters in the simulation. This paper presents the details of aerodynamic simulation process of a Crossover and its validation with the experimental results available from the wind tunnel tests. The results are compared for different configurations such as- closing the grille openings, removing the rearview mirror, adding ski-rack and using different tyres. This study also includes the effect of different wind speeds and yaw angles on the coefficient of drag.

This paper describes a Computational Fluid Dynamics (CFD) technique for evaluating the effectiveness of an intake manifold/ EGR system. The effectiveness of the intake manifold is defined in terms of equal distribution of EGR to individual cylinders. The procedure described in this work is unparalleled, since the available testing techniques are inadequate to make measurements of the actual EGR distribution. This paper also outlines a 1D - 3D coupling approach to apply transient boundary conditions on the CFD model. As part of this study, the development of an intake manifold/ EGR system is described under different operating conditions. Different intake manifold designs are also compared. Various parameters affecting the distribution of the EGR are discussed.

The design and development of cylinder head and crankcase is the most critical activity in a new Engine program. These two components are subjected to complex and cyclic loading as a result of the interaction between fluid flow, heat transfer and mechanical loads. Apart from structural durability, bore distortions, the need of effective sealing at the head and crankcase joint has to be ensured. The physical validation of the structure requires the components to be developed and this is a long phase including the validation itself. Any modification due to failure or optimization at this stage can be a set back in meeting the deliverables within the given time lines. Physical testing does not provide any means of visualization of the flow and the structural deformation modes.

This paper discusses flow through the front end of a vehicle comprising all the underhood/underbody components. Two approaches used to model the fan to predict the front-end airflow in a full vehicle model using Computational Fluid Dynamics (CFD) are presented. The approaches discussed here are the Moving Reference Frame (MRF) model and the fan plane model. Both cold and hot flow conditions are carried out for the full vehicle model. This paper also outlines the determination of fan performance curves numerically. The data from the fan performance curves thus obtained can be used in a fan plane model. The paper also discusses two methods to determine the recirculation factor in front-end flow studies namely, the user-defined scalar (UDS) method and the heat balance method.

This paper discusses application of Computational Fluid Dynamics (CFD) in the development and evaluation of a diesel engine cooling system. Commercial CFD codes are effective in developing and analyzing engine cooling systems including the complex cooling jacket. A complete cooling circuit model developed based on 1D - 3D coupling is discussed. This approach is both cost and time effective. The coupled model enables the prediction of realistic flow rates through the cooling jacket outlets. Cooling jacket system resistance is also determined. The paper discusses various approaches for conducting heat transfer and thermal analysis of engine crankcase and head. Boundary conditions for the thermal analysis are obtained from in-cylinder CFD simulations for diesel spray and combustion. The phenomenon of nucleate boiling, its mathematical modeling and its effect on heat transfer is discussed.

Results of Computational Fluid Dynamic (CFD) analyses of different diesel fuel injector nozzle configurations using a commercial CFD code are presented here. The emphasis of this study is on comparing cavitation models available in the commercial code with respect to their mathematical approach. One of the models is a simple single-phase model based on the Barotropic equation of state, while the other model is a two-phase model based on the bubble dynamic considerations. Results are compared for various 3-D diesel injector nozzles using the two cavitation-modeling approaches. Simulation results are observed to substantiate some of the experimentally established facts like; nozzle efficiency improvements by using techniques like rounded orifice inlets and conical orifices. Also, simulation results agree well with the experimental results. Spray characteristics are predicted based on a primary breakup model.

Precise control of fuel delivery and injection pressure is essential in modern DI diesel engines. Electronically controlled high-pressure injection systems provide features required by modern diesel engines such as precise injection quantity, flexible injection timing, flexible rate of injection with multiple injections and high injection pressures. A comprehensive experimental and numerical investigation has been performed to determine the influence of operating parameters and critical injector design parameters on the dynamic performance of advanced high-pressure electronically controlled diesel injection systems. The injection systems compared in this study are the High Pressure Common Rail (HPCR) and the Hydraulic Electronic Unit Injector (HEUI). Experiments are carried out using a Bosch type injection-rate meter. Needle lift, injection-rate/rate shape, and injection pressure are measured.

In diesel injector nozzles, the shape of the orifice entrance and the sac-volume play a significant role in determining the orifice internal flow characteristics and the subsequent spray formation process. The sac-volume of the injector nozzle determines injection characteristics like injection rate shape and discharge coefficients. The sac-volume is also important from emissions point of view, in that it controls the amount of Un-Burnt Hydrocarbons (UBHC). This paper demonstrates the use of commercial dynamic and computational fluid dynamics (CFD) programs in predicting the flow characteristics of various nozzle orifice and sac-volume configurations. Three single orifice nozzle tips with varying sac configurations and orifice entrance shapes are studied. Transient simulations are carried out in order to compare the injection rates, discharge coefficients and internal flow characteristics for the nozzle tips. The simulation results are compared with experimental results.