Abstract

The fuel spray in gasoline engines problem has been an issue of importance for creating a suitable mixture during the engine load and speed variation to avoid knocking. This paper describes theoretical and experimental investigations for an important stage of injected gasoline called the primary fuel spray. This stage two dimensional (2D) is challenging because of the difficulty in determining velocity and length at very short time, so it was studied specially the dispersion of the sheet by using the linear instability sheet atomizer model (LISA). Experimentally the Phase Doppler Anemometer (PDA) is used at laboratory of Cardiff university to check the sheet length. The paper concerned on study the effects of some parameters on primary spray characteristics like as liquid fuel sheet thickness, velocity and length which are described the initial value of the fuel spray droplet. Injection pressure was varied 5, 13 and 14 MPa under combustion chamber pressure (ambient pressure) (0.1, 0.5 MPa), while the nozzle diameters is varied (0.2, 0.3, 0.4, 0.5 mm). LISA model was used to solve this stage of spray by using Pressure-Swirl type of injector. The results show at an increase of the injection pressure, the velocity increased, while the sheet thickness and length were decreased. When the ambient pressure was increased; sheet velocity decrease and slightly decreasing happened in sheet length and thickness. Comparison the results with experimental results showed a good agreement.