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A numerical model to assess the aerodynamic performance of typical automotive cooling fan stators or support arms is presented. Under real operating conditions, the flow over stators or support arms resembles bluff body flow. Hence, the time and spatial resolution are selected based on previous numerical simulations for the flow around a normal flat plate. Turbulence modeling is based on the Unsteady Reynolds-averaged Navier-Stokes (URANS) equations retaining the Boussinesq eddy-viscosity hypothesis. The ability of the URANS model to predict the periodic nature of the flow is demonstrated here. Furthermore, comparison with experimental data shows that the proposed numerical model can predict the global flow parameters, namely lift and drag within good accuracy. As a first attempt to assess the interaction of the cooling fan with its system environment, the proposed numerical model is expanded to model the interaction of the fan blades with the adjacent stators or support arms.

A novel, simple and rapid method for predicting the performance effects of blockage downstream of an automotive cooling fan is presented. Fans are often tested without downstream blockage and, thus, the performance is considerably different when the fan is mounted in a vehicle as part of a cooling system. An easy to use tool is needed that can quickly predict fan performance modifiers. The suggested approach is able to predict the significant effects of a blockage behind the fan. Two fans were analyzed with this new method. Comparison charts between tests and predictions showed good agreement over a range of blockage distances. Based on the results the method is considered beneficial for initial design procedures. Although the agreement was poorer at very close separation distances such small gaps are less commonly utilized in practice. Further work is needed to include those distances in the present model.

The choice between using stators or support arms downstream of an engine cooling fan depends on the lift and drag forces. A transient, Computational Fluid Dynamic (CFD) simulation was performed of a stator configuration. Results for an unsteady (sinusoidal) inlet condition, based on Laser Doppler Velocimetry (LDV) data of a flow downstream of an automotive fan, are compared to steady inlet conditions. Vortex shedding and suction side separation were observed with a steady inlet condition. Due to the vortex shedding the lift coefficient fluctuated. The mean lift coefficient was 68% lower than the published data used for design. The mean lift coefficient observed was similar to what was expected from a cambered plate of 2% camber at the same angle of attack. The performance of the stators under unsteady inlet conditions was different than under steady inlet conditions and therefore steady flow velocities are not an effective input to design.

Typical automotive engine-cooling fan assemblies include an electric motor having a driveshaft coupled to a fan. The typical fan includes a hub, which extends from the driveshaft to the root of the fan blades. Radial ribs are incorporated within the hub to stiffen the fan structure. The fan hub including the ribs pulls cooling air through the motor, thus preventing it from overheating. Experimental tests and computational fluid dynamics (CFD) simulations have been carried out to investigate the effects of fan hub configurations on cooling airflow through the electric motor in automotive cooling fan systems. It has been found that radial ribs on the fan hub have significant effects on drawing cooling air through the motor. The comparison of the simulation results with the pressures measured in laboratory experiments show good agreement.

The Fluidyne, or liquid piston stirling engine, has many characteristics which make its use in developing nations particularly attractive. Besides being compatible with the use of lowgrade heat sources, the machine is simple to manufacture using a variety of low cost materials and is exceedingly reliable. This paper uses a summary of fluidyne experience to evaluate applications of the fluidyne to water pumping requirements in developing countries for purposes including domestic, livestock, and irrigating uses for water pumping. Possible sources of energy are evaluated in the light of availability and needs. Environmental, economic, and social benefits are also examined. Particular applications of the fluidyne to existing situations in China are evaluated in detail.