A Comprehensive Experimental Investigation on the PFI spray impingement: Effect of Impingement geometry, Cross-Flow and Wall Temperature

Abstract In this work, an experimental study on the effects of the impingement geometry, the cross-flow intensity and the wall temperature on the characteristics of an impinging port fuel injection (PFI) spray was conducted. The transient development of the impinging spray was recorded by a high-speed camera with Mie scattering. Based on the high-speed images, the spray tip penetration ( S ) and the impinged spray height ( H w ) were obtained. The results show that with the increase of the impingement distance ( L w ) , S increases and H w decreases at the same time after the impingement. As the impingement angle ( θ w ) increases , S decreases while H w first increases and then decreases. With the increase of the cross-flow velocity ( U c ) , less part of the spray impinges onto the wall, and S significantly increases. As the wall temperature ( T w ) rises, S does not show much variation. However, H w increases gently for T w lower than 420 K, and it increases sharply for T w higher than 420 K due to the Leidenfrost mechanism. The effects of the above factors ( L w , θ w , U c , T w ) on S and H w were finally evaluated and compared through the introduction of a contribution index.