Nozzle discharge velocity

Nozzle Diameter, d Nozzle exit diameter will be equal to or less than the diameter of the line feeding the tank. For a known flow rate of fluid supplied to the jet, the diameter is set by the largest size that will satisfy the requirement that the jet be turbulent or will satisfy the nozzle discharge velocity requirement (if the jet is denser than the tank liquid). For a turbulent flow requirement (both heavy and light jets) ... 

Mid Stage pressure nozzle discharge velocity stage mass flow... 

The mid-stage pressure is needed if we are to calculate the nozzle discharge velocity and the nozzle flow. In fact, the mid-stage pressure is the same as the pressure at stage outlet for an impulse nozzle, while the midstage pressure for a reaction stage may be found from equation (15.21). 

In Fig. 1.20, specific energy consumption is shown as a function of the drying rate, with the nozzle discharge velocity as a parameter as an example, a nozzle... 

As discharge velocity at the nozzle outlet increases, the following states appear in succession dripping, laminar jet breakup, wave disintegration, and atomization. These states of fiow are described in a pi space Re, Fr, Wep, whereby Wep = pv dp/a represents the Weber number formed by the droplet diameter, dp. To eliminate the fiow velocity, v, these numbers are combined to give... 

By exceeding a certain discharge velocity, turbulence forces increase to such an extent that film disruption takes place immediately at the orifice. Now the droplet size is independent of the film thickness. This state of atomization is described by the critical Weber number. Measuring data obtained with hollow cone nozzles of different geometry and pure liquids as well as lime-water suspensions are represented in Figure 19. Wep,crit... 

As an illustration, suppose the surface of water in a reservoir is 500 ft above the level of the site of a power plant and that there is available a flow of 200 ft3/s. In this case, H = z = 500 ft and P = 62.4 x 200 x 500 = 6,240,000 ft lb/s, or 11,340 hp, which is the total power available. If in the pipeline the friction loss is hf = 25 ft, then the power lost by friction is Whf and is seen to be 567 hp. Again, suppose a nozzle discharges 50 lb of water per second in a jet with a velocity of 120 ft/s H = V2/2g = 224 ft. Then the available power in the jet is 50 x 224/550 = 20.3 hp. The expression power equals force applied times velocity of the point of application of the force cannot be used in the preceding case, because it has no physical significance, as there is no force applied to anything, nor is there any point of application. In the case of a jet, the force it might exert would depend upon what happened when it struck an object, and the power produced would depend upon the velocity of the object. But the available power of the jet is a definite quantity, no matter what it acts upon or whether it ever acts upon anything. 

Va = velocity of atomizing air at atomizer, ft/h Ds = diameter of pressure-nozzle discharge orifice, ft pj = density of dryer gas at exit conditions, Ib/ft ... 

For a Mach number of 2.0 (based on conditions at the nozzle throat) the discharge velocity is 1,079.4 ms". Substitution of this value in Eq. (7.22) allows calculation of the pressure ratio ... 

Figure 3. Discharge velocity as a function of time for three values of the nozzle diameter, 0.3 to 0.6 m.

As an example, let us take the case of a convergent-only nozzle being fed with initially stationary air at 20 bar and 400°C. The design efficiency is 0.97. The geometry of the discharge manifold is such that we may assume that the discharge velocity will continue... 

We may assume that the nozzle will be designed to produce a supersonic discharge velocity, and that the design pressure ratio will coincide with the lower critical discharge pressure ratio for the design inlet conditions, i.e. (pi/por)lo = (Pimi2/Por)lo-The nozzle will be choked at this point, and this implies that the pressure at the throat will be at its critical value. The associated throat critical pressure ratio is given by equation (14.55) ... 

Discharge velocity and mass flow in a convergent-divergent nozzle... 

---