Impinging jet atomization

Actual values of SMD (or some other mean droplet size) for various types of fuel injectors are given for orifice injectors (23, 25, J+5, 47, 61, 95, 107, 113) swirl injectors (8, 18, 20, 26. 34, 46, 63, 76-78, 81, 87, 93, 99, 100, 104, 112, US, U8, 123) air-blast atomizers (5, 13, 33, 50, 64, 74, 94, 101) impinging-jet atomizers (30) rotating-element atomizers (7, 28, 53) and droplet formation caused by collapse of gas bubbles rising through a liquid surface (32, 91). Maximum values of x are reported for orifice injection (88) and for air-blast atomization (72). [The air-blast atomization mechanism may be controlling when the air blast is in reality only a high relative velocity between the air and the injected liquid (61).]... 

Ibrahim E, Przekwas A. (1991) Impinging jets atomization. Phys Fluids A 3(12) 2981-2987. 

Keywords Area ratio Hypergolic liquids Impinging jet atomization Mixing ... 

Waves form on the surface of the sheet and grow until the sheet breaks up into small droplets. The generated spray has an elliptical cross section with its major axis in the plane of the liquid sheet. The sizes of the droplets formed from the impinging jet atomizers are directly related to the thickness of the liquid sheet. Generally, the is inversely proportional to the radial distance from the impingement point and other parameters. This chapter provides a description of the characteristics of liquid sheets formed by impinging jets and provides methods to determine average droplet sizes produced by such nozzles. 

Kang, B.S., Shen, Y.B., and Poulikakos, D., Holography Experiments in the Breakup Region of a Liquid Sheet Formed by Two Impinging Jets, Atom. Sprays, Vol. 5, pp. 387-402, 1995. 

Shen YB, Poulikakos D., Impinging jet atomization at elevated and supercritical ambient temperature and pressure conditions. Experimental Heat Transfer, JAN-MAR, Vol. 11, Issue 1, pp. 23-40, 1998. 

A number of techniques have been evolved to disperse liquids in gases in the form of fine droplets. The various atomizing techniques are jet injections, fan sprays, centrifugal nozzles, twin fluid atomizers, impinging jets, and rotary... 

Airstream Atomization and Impinging Jets. The very powerful effect of high-pressure air as an atomizing agent has been demonstrated by Joyce (SB). Lewis and associates... 

There are numerous experimental as weU as theoretical studies on the mechanisms of atomization of the impinging jets. These studies [7-36] show that when two jets collide they form a sheet in the direction perpendicular to the plane of the jets. 

Arai, M. and Saito, M., Atomization Characteristics of Jet-to-Jet and Spray-to-Spray Impingement Systems, Atom. Sprays, Vol. 9, pp. 399-417, 1999. 

H. Ryan, W. Anderson, S. Pal, and R. Santoro Atomization characteristics of impinging Jets. Journal of Proportional Power, 11, 135-145 (1995). 

Because the highest possible interfacial area is desired for the heterogeneous reaction mixture, advances have also been made in the techniques used for mixing the two reaction phases. Several jet impingement reactors have been developed that are especially suited for nitration reactions (14). The process boosts reaction rates and yields. It also reduces the formation of by-products such as mono-, di-, and trinitrophenol by 50%. First Chemical (Pascagoula, Mississippi) uses this process at its plant. Another technique is to atomize the reactant layers by pressure injection through an orifice nozzle into a reaction chamber (15). The technique uses pressures of typically 0.21—0.93 MPa (30—135 psi) and consistendy produces droplets less than 1 p.m in size. The process is economical to build and operate, is safe, and leads to a substantially pure product. 

---