An experimental investigation of high pressure cavitating atomizers

Haiyun Li, Purdue University

Abstract

Cavitation in spray and atomizing orifices remains a design problem with long-term implications in many industrial applications. Diesel engine injectors and numerous industrial sprays operate in regimes where cavitation is present and can dominate the overall characteristics of the internal flow field. A test facility is constructed to conduct experiments and flow visualization in a three-dimensional circular orifice at pressures up to 200 MPa (30,000 psi). The diameters of orifices used in this test are 0.2 mm to 0.4 mm and are similar to the real size of Diesel fuel injectors. Two types of orifices are studied, one with the hole normal to the surface and the other with the hole at an angle. The tilted orifices are used to simulate the real working geometry of Diesel engine injectors. An imaging system is used to obtain high resolution photographs of cavitation in these orifices. Both the cavitating flow inside the orifice and the spray outside the orifice have been studied. The mass flow for different orifices has also been measured at different injection pressures. Present computer models cannot completely predict details such as unsteady three-dimensional flows with phase changes and turbulence. Development of such models, for either injector design or fluids research, is hampered by the extreme lack of data for cavitation at such small length scale internal flows. This research project concentrates on experiments about cavitation in the geometry, length scales, and pressures of Diesel fuel injectors.

Degree

Ph.D.

Advisors

Collicott, Purdue University.

Subject Area

Aerospace materials

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