Optimisation of a Hot Air Duct on a Turbo-Intercooler in a Heavy-Duty Diesel Engine Using Computational Fluid Dynamics

Since locomotive diesel engines have high production and testing costs, researchers have carried out numerical investigations to assess various aspects of their design, including the hot air duct. In this process, they have aimed to find the optimum design in order to improve the flow efficiency and to provide equal air intake to the air coolers. Optimisation of the air channel attached to the turbo-air cooler in a locomotive engine at the design stage would serve as a reference in terms of determining the air entry points to the air cooler and the correct positioning of the air coolers on the engine. Various designs have been proposed for a hot air duct mounted on the turbo-air cooler in a heavy-duty diesel engine, and these designs have also involved other engine parts. In the present study, the hot air ducts in different designs are compared in terms of velocity distributions using computational fluid dynamics. First, a model with an S-bend, based on the current engine, is analysed; a model is then created by removing the S-bend, and the velocity distributions are compared between the two models. The flow homogeneity is found to be disrupted in the model with the S-bend (Model 1), whereas the flow is distributed more homogeneously in the model from which the S-bend was removed (Model 2). In Region A of Model 1, the average velocity was 43.300 m/s, while the value in Region B was 33.712 m/s. In Region A of Model 2, the average velocity was 39.031 m/s, whereas in Region B, it was 34.104 m/s. In the revised model, the flow tended to follow the pipe from the upper part, due to the downward orientation of the pipe after the Y-split used for routing to the dual air cooler. The downward slope was therefore removed after the Y-split, and the velocity distributions were compared. In the model without the S-bend from which the slope had been removed after the Y-split, the flow was distributed homogeneously at the top and bottom of the pipe. This model would provide equal air distribution to the air cooler inlets in a diesel locomotive engine with dual air coolers.