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The subcooled flow boiling was an effective heat transfer method by using latent heat of coolant in modern engine cooling passages. The cylinder head temperature of internal combustion (IC) engine could be maintained below the damaged temperature. Hence, in this paper, the Eulerian two-phase Rensselaer Polytechnic Institute (RPI) subcooled boiling model including several sub-models was employed to study the heat and mass transfer in cylinder head cooling passages. Firstly, the two-phase RPI boiling model was validated by Robinson’s experimental data with the glycol solution of 50% volume fraction as working coolant. The simulated results were in good agreement with experimental data. Then, the Eulerian two-phase RPI subcooled boiling model could be applied to simulate subcooled flow boiling heat transfer phenomenon in practical engine cooling passages. Furthermore, in order to investigate the cylinder head temperature field, the temperature of 20 points was measured.

An elliptical influence model of obstacle vehicles was proposed based on the artificial potential field method. The novel mathematical model of lane changing trajectory planning including the lane boundary potential field, the multi obstacle vehicles potential field and the moving target potential field was established to simulate the trajectory planning of intelligent vehicle lane changing under the actual freeway scene. The result shows that the planning trajectory is highly consistent with real one under good lane changing conditions. Furthermore, this kind of the trajectory was introduced into CARSIM software and simulated. The findings show that the actual trajectory is also consistent with the target trajectory. Both the front wheel steering angle and the lateral acceleration were satisfied with the dynamic constraint of vehicle, which has well stability and comfort.

Oscillating cooling characteristics in piston oil cooling gallery of internal combustion engines were simulated by adopting Coupled Level Set Volume of Fluid method and Arbitrary Lagrangian Eulerian dynamic grid technique. The influence relationship of structure parameters and oil filling rate to the average temperature of oil gallery was studied by response surface method. The optimal structure parameters and oil filling rate were acquired by Multi-Objective Genetic Algorithm method.

The objective of this present research is to investigate the influence of bubble waiting time coefficient on subcooled flow boiling heat transfer in internal combustion engines and propose an approach to predict its value. The three-dimension simulated cooling jacket structure of valve bridges for forced water-cooling system was developed respectively. The numerical model for subcooled flow boiling based on two-fluid approach was established and calculated. Numerical results suggest that the bubble departure diameter increases with the increasing wall superheat or decreasing inlet subcooling. And the proportion of the quenching heat flux gradually rises and its peak value is delayed along the direction of the higher wall superheat when the subcooling degree increases. The bubble waiting time coefficient has been found to have a significant impact upon the boiling heat transfer.

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).