Jet formation

The electrospinning experiment needs a relatively simple system. Components include a voltage source that is capable of generate high potential differences ( 0.5 kV/cm), a counter electrode, a viscous polymer solution and a means of pumping this solution. 

While the solution is forced out of a capillary, through gravity or an external force, there are forces acting immediately on the liquid, such as gravity, surface tension and electrical voltages. These forces compete and balance each other to form the Taylor cone and, depending on the equilibrium of the cone, droplets or jets can be ejected. 

Taylor estimated that the surface tension is perfectly balanced by the normal voltage to create a cone with an apex angle of 98.6°. It is assumed that this cone has no material loss, and from there, scaling laws were created to predict the diameter of the drop and the current as a function of fluid and flow properties [17], 

Hartman et al. [18] developed laws that link the diameter and the surface charges from emitted fibers of a Taylor cone, according to Eqs. 4.5 and 4.6  

Equations 4.5 and 4.6 do not apply in the case of instabilities that result in fibers with nanoscale diameters. Without a proper control of operating conditions or fluid properties, the product can be fibers mixed with drops, or, if the solvent evaporation does not occur, the fibers collected on the counter-electrode will still be wet. 

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The distributor should be sized so that the hole velocity is greater than the jet formation velocity. As the velocity is increased, the jet reaches a maximum length at which it breaks into drops of approximately uniform size. It has been found that at this velocity the drop surface area... 

Schiferl [66] concludes from the study of jet formation in titanium that ... 

E. M. Pugh, R.J. Eichelberger, and N. Rostoker, Theory of Jet Formation by Charges with Lined Conical Cavities, J. Appl. Phys. 23, 532-536 (1952). 

Simon, J. and DiPersio, R., Jet Formation and Utilization, in Proceedings of the 12th Annual Symposium on Behavior and Utilization of Explosives in Engineering Design, Albuquerque, NM, pp. 201-213, March 2-3, 1972. 

Walters, W.P., Influence of Material Viscosity on the Theory of Shaped-Charge Jet Formation, US Army Ballistic Research Laboratory Memorandum Report No. ARBRL-MR-02941, Aberdeen Proving Ground, MD, 43 pp., August 1979. 

Fig. 6. Cavitation near a surface. Jet formation from laser-induced cavitation in water at 75,000 frames/second. Sequence is from left to right, top to bottom the solid boundary is at the bottom of each frame. From Ref. 66.

Duchemin, L., Popinet, S., Josserand, C., and Zaleski, S. (2002). Jet formation in bubbles bursting at a free surface. Phys. Fluids 14, 3000-3008. 

Theory of Jet Formation in Lined Shaped Charges. See Detonation BMPT (Birkhoff-MacDougall-Pugh-Taylor) Theory of Jet Formation in Shaped Charges... 

A fuller explanation of the BMPT theory, and their equations defining liner collapse jet formation is found in Cook (Ref 2)... 

Simultaneously. with the work carried out in US, a group of scientists was engaged in similar studies in Great Britain with comparable results and success. Indeed, the currently accepted theory of liner collapse and jet formation was worked out there independently from Americans by G.I. Taylor from radiographs obtd by T.L. Tuck, even before those obtd at BRL... 

Jan 1954 4la) R.I. Eichelberger, Reexamination of Theories of Jet Formation and Target Penetration by Lined Cavity Charges , Carnegie Institute of Technology, Dept of Physics, CEL Rept No 1,... 

Spencer, The Determination of Reaction Rates of Nonideal Explosives from Shaped Charge Penetration Data , Univ of Utah Inst for Study of Rate Processes, TechRept No XLVIl(1955) Contract N7-onr-45107 46) R.J. Eichelberger, JApplPhys 26, 392-402(1955) (Re-examination of the unsteady theory of jet formation by lined cavity charges) 47) Ibid, 27, 63-8 (1956) (Experimental test of the theory of penetration by metallic jets) 48) T.C. Poulter ... 

Shaped charge for perforating oil well casing) 55) Cook (1958), Chapter 10, "Principles of Shaped Charges , which includes History (pp 226-28) Explosive factors in cavity effect (228-29) Application to mass loading in different geometries (229-35) Detonation pressure in nonideal explosives (235-44) Mechanism of linear collapse and jet formation (244-47) Metal-... 

Birkhoff-MacDougall-Pugh-Taylor Theory of Jet Formation. See next item... 

Jet Formation in Shaped Charges. See Detonation BMT (Birkhoff-MacDougall-Pugh-Taylor) Theory of Jet Formation in Shaped Charges in Vol 4 of Encycl, p D226-R and Detonation, Munroe-Neumann Effect (or Shaped. Charge Effect) and Lined-Cavity Effect in on pp D442-Rff... 

In carrier type guns ranging from 2 5/8 to 5 inches OD, the Jet Perforators are threaded on a strand of Primacord and loaded into the gun, a steel tube which is sealed at both ends. The gun serves to control the standoff distance and prevents the well fluid from interfering with the jet formation. For through-tubing completion a smaller version of the carrier-type perforator can be supplied... 

Detonation BMPT (Birkhoff-Macdougall-Pough-Taylor) theory of jet formation in shaped charges 4 D226... 

Figure 1.97 Jet formation by reopening of the cross-sectional flow area for a multi-lamination stream which was before focused in the slitshaped interdigital micro mixer [20]...

Figure 1.98 Pure multi-lamination flow pattern (top, 10 ml h-1) and superposed by focusing and reopening/jet formation (bottom, 2 I h-1) in the slit-shaped interdigital micro mixer visualized by blue-colored water dilution imaging [20] (by courtesy of AlChE).

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