Experimental investigation of the coolant flow in a simplified reciprocating engine cylinder head

Abstract

The chapter develops an experimental study of the coolant flow in a simplified transparent model of an internal combustion engine cylinder head to build a data bank to validate CFD codes. Simple laws of engineering relevant for pressure losses are provided in the chapter. A set of two-dimensional cylindrical tubes perpendicular to the flow models the cooling circuit of a 16 valves cylinder head. The test rig-set-up consists in a closed circuit with a pump. Two measurement techniques, laser doppler anemometer (LDA) and particle image velocimeter (PIV) are used. Mean values, moments, and vorticity are determined. Pressure on the various cylinders and head pressure losses are also measured. The effect of separation on downstream tubes is investigated. As a simple test, comparison with a conventional k-є code is provided. A model representing the essential hydrodynamic features of a cooling circuit that is more complex than a regular tube arrangement is developed. The model can be considered as two dimensional and easy to study by computational fluid dynamics. The measurements methods used are complementary, and a relatively complete database is obtained. A head pressure loss coefficient varying as the -1/5 power of the Reynolds number is proposed. The sensitivity of this law to the geometric location of the pipes is to be analyzed. The exit is also associated to the strong turbulent intensity. A crude test of a commercial code is performed. The separation zones and their interactions with inner obstacles are not predicted with a sufficient accuracy.