Search Results

A steady-state flowbench measures the mass and angular momentum flux (swirl and tumble) for a given cylinder head intake port design over varying valve lifts and pressure drops. From these two measurements, enhancements in volumetric efficiency and burnrate can be determined. This methodology, however, requires the production and experimental testing of multiple cylinder head castings or soft-prototypes. To help reduce the number of hardware design iterations, an analytical methodology has been developed which uses a new computational fluid dynamics (CFD) simulation tools called PowerFLOW. From a solid model of the cylinder head, PowerFLOW uses automeshing which produces a 10 million Cartesian volume mesh in 4 CPU hrs. The lattice Boltzmann technique used by PowerFLOW is inherently parallel resulting in steady-state results on this mesh in 36 CPU hrs. This paper present a comparison of numerically obtained mass flow rates from PowerFLOW to experimental flowbench data.

The current ability of the Virtual Aerodynamic/ Aeroacoustic Wind Tunnel to predict interior vehicle sound pressure levels is demonstrated using an automobile model which has variable windshield angles. This prediction method uses time-averaged flow solutions from a lattice gas CFD code coupled with wave number-frequency spectra for the various flow regimes to calculate the side window vibration from which the sound pressure level spectrum at the driver's ear is determined. These predictions are compared to experimental wind tunnel data. The results demonstrate the ability of this methodology to correctly predict wind noise spectral trends as well as the overall loudness at the driver's ear. A more sophisticated simulation method employing the same lattice gas code is investigated for prediction of the time-accurate flow field necessary to compute the actual side glass pressure spectra.