Introductory measurements of in-cylinder flow past intake valve ports with a film split-fiber probe

Abstract

A new steady flow test bench test facility has been designed and fabricated for exploration of complex three-dimensional flowfields inside a cylinder of an internal combustion engine. An engine cylinder head of a currently produced car engine with four head valves is utilized as an inlet section of the newly built test bench test. No piston is located in the cylinder and the intake valves are not periodically operated. They remain open during the test periods. An extensive set of initial experimental data has been acquired for both open intake valves and for the location of the probes at two different axial stations in the engine cylinder. The experimental technique of thermo-anemometer split-fiber probes is employed in this research work, which is a novelty never applied before to this class of flows. The probe properties are explained in the paper with emphasis on the probe directional characteristics. The verification tests proved the operational readiness of the new test bench to acquire reliable experimental data at a range of flow conditions simulating real engine settings. The acquired data set base will be used for validations of improved CFD engine design codes. An analysis of the initial set of experimental data clearly indicates that two vortices, or more likely down-flowing spiral flow structures. are present side by side in the cylinder. Mutual interaction of these two flow structures and the ability to generate faithful numerical simulation of this flow pattern for additional planes of measurement and various valve openings will be reported separately.