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This paper is concerned with prediction of heat dissipation effect by establishing a 3d geometric model of the radiator group for a ribbon-tubular radiator of a mining dump-truck. By using the CFD approach the airflow characteristics of the radiator group are numerically calculated, and the resistance characteristic and heat transfer performance are analyzed thus the matching point of the fan is calculated, and the heat transfer performance of the water-side is simulated. Then, according to the relative heat transfer theory, the inlet and outlet water temperature of the radiator group under idling condition is obtained by analytical method. The experiment is done subsequently. The maximum deviation rate between the results of the simulation and the experiment is 6.4%, which can meet the engineering requirement and well predicts the heat dissipate performance of the radiator group. The result indicates that by combining the CFD numerical simulation with the analytical method the heat dissipation of the radiator group can be predicted effectively.

For study the law of urban buildings, in particular, the buildings at both roads’ sides in crossroads impacting on the diffusion of automobile exhaust, using CFD, combined with meteorological wind，simulates a crossroads automobile exhaust diffusion processing during waiting 35s. The results are following: in poor circulation areas, CO volume fraction in the buildings near-Earth space is up to 1.0e-7 and more than 100 times average value of the entire study area, so buildings structural layout has great influence. After Analysis, propose that local meteorological wind direction and speed should be considered and different height gradient design should be selected in buildings structural layout, so that the exhaust spread rapidly and drift to the urban high altitude, in order to improve air quality.

Various return oil channels of a large self-dumping truck hydraulic tank don’t work synchronously brings the exit temperature fluctuations, traditional heat balance calculation can’t get some point temperature in tank, so it can’t be used to analyze temperature fluctuations. Selecting RNG k-εturbulent model and using CFD method，this paper analyzes flow field in the hydraulic tank of a certain large self-dumping truck at first, then according the principle of enhancing heat exchange, proposes two structure improved schemes, and contrasts the simulation result of two schemes, The results show that the two improved schemes reduce the tank exit temperature fluctuations and the high local temperature at different degrees, and the temperature fluctuations reduce range of the best scheme is 86.51% when the initial hydraulic oil temperature is 40°C.