In other cases, a cold flow CFD approach is sufficient to identify a system restriction curve. In some cases, conjugate heat transfer is needed to accurately predict top tank temperature. Typical cooling packages also include a cooling fan which is crucial for delivering the ambient airflow when the vehicle is in parking or idling condition.Ī CFD analysis can be performed under various fan speed conditions. The down-select of an optimized cooling package can be completed before being integrated into the vehicle’s system. This can be achieved using computational methods for fluid dynamics. It is useful to evaluate pressure drop across the radiator component based on the given fin density at the early stage of the radiator design process. In general, the larger the radiator size, the greater the restriction to the airflow. In order to meet airflow and top tank temperature requirements, vehicle front-end cooling packages must be properly sized, designed, and installed in high horsepower engines. This is, in part, due to the necessity of meeting stringent emissions requirements. The high horsepower 15L diesel engine is known to produce an undesirable high-heat rejection rate. In this article, I will briefly discuss my past experiences of using computational methods for fluid dynamics for different HVAC system design performance evaluations. The overall operating efficiency of an HVAC system depends as much on proper design as on installation. Computational Methods Examples of CFD Analysis in HVAC System DesignĪir conditioning systems, fans, and blowers are commonly installed in residential and commercial buildings to maximize thermal comfort. For example, automotive cooling packages including a radiator, condenser, and charge air cooler are designed to meet the requirements of an internal combustion engine. In general, they are designed in an integrated form to efficiently manage and deliver energy in and out of the system. They consist of several cooling and heating components specifically designed to meet energy consumption requirements. The CFD prediction of the peak air temperature during the hot-soak is validated against a published test result.HVAC systems are widely used in the automotive, construction, oil and gas, and aerospace industries. In addition to transient mass, momentum and energy solution, it also solves for transient species transport of dry air and water vapor mixture for the humidity effect of the cabin air. A rapid 3-D coarse CFD calculation is employed based on simplified cabin geometry to predict overall temperature distribution. On the other hand, the CFD model in this report is part of a coupled system simulation involving multiple 1-D or 3-D modeling components. This coupled method enables right-sizing HVAC systems against realistic transient operations instead of peak operations to reduce compressor load, thus to achieve overall fuel economy improvement. It demonstrates that the coupled method can simulate fully transient HVAC system operations in a vehicle. The coupled simulation consists of an A/C and an Air-Handling (HVAC module) system models, and a cabin CFD model. We then apply this integrated tool to simulate a transient A/C operating cycle including hot-soak and cool-down of a cabin. In this report, first, the implementation of this fully transient, coupled method between FLUENT CFD and e-Thermal is introduced. This toolset utilizes COM software interface standard of MS Windows for inter-process communication at simulation run-time to synchronize the two applications and to exchange data. A multidisciplinary toolset integrating ANSYS FLUENT CFD solver and GM in-house thermal system design tool - e-Thermal has been developed to design automotive HVAC systems.
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