Jet problems

With these assumptions one may readily solve the coaxial jet problem. The only differential equation that one is obliged to consider is... 

Jet problems. These include low motive-steam pressure, excess wear on the steam nozzles, high condenser backpressure, and air leaks that exceed the jet s capacity. To determine whether a poor vacuum in a surface condenser is due to such jet problems, consult the chart shown in Fig. 18.4. Measure the surface condenser vapor outlet temperature and pressure. Plot the point on the chart. If this point is some-... 

Much of the procedure for the analysis of jet stability has already been set down in connection with the discussion of undamped surface waves on deep water. A fundamental difference in the jet problem from plane deep water waves is that it is axisymmetric with an imposed characteristic length scale equal to the jet radius a. Since the undisturbed jet is considered to be inviscid and in uniform flow, it can be reduced to a state of rest simply by a Galilean transformation. With gravity neglected and only surface tension forces acting, the pressure at any point within the jet is -I- ala. This then describes the basic flow needed for the first step of the stability analysis. 

The linearized dynamic boundary condition is physically the same as given by Eq. (10.4.7) for the plane surface wave, which with allowance for the cylindrical symmetry of the jet problem may, from the Young-Laplace equation, be written... 

Given its efficiency, BEM has been applied to a variety of problems involving large deformations of a free surface. Several solutions have been developed for problems related to the nonlinear evolution of water waves, [9-11] and for problems related to nonlinear deformations of both viscous and inviscid drops [12,13]. BEM has been applied to several applications of creeping (Stokes) flows in liquid columns [14-16] and in annular layers [16]. Inviscid solutions have also been obtained for both infinite [16] and finite-length [13] liquid jet problems, as well as for dripping flows [13], fountains [13], and fluid sloshing problems [17]. 

The properties required by jet engines are linked to the combustion process particular to aviation engines. They must have an excellent cold behavior down to -50°C, a chemical composition which results in a low radiation flame that avoids carbon deposition on the walls, a low level of contaminants such as sediment, water and gums, in order to avoid problems during the airport storage and handling phase. 

The properties linked to storage and distribution do not directly affect the performance of engines and burners, but they are important in avoiding upstream incidents that could sometimes be very serious. We will examine in turn the problems specific to gasoline, diesel fuel, jet fuel and heavy fuel. 

Rankine Cycle Thermodynamics. Carnot cycles provide the highest theoretical efficiency possible, but these are entirely gas phase. A drawback to a Carnot cycle is the need for gas compression. Producing efficient, large-volume compressors has been such a problem that combustion turbines and jet engines were not practical until the late 1940s. 

Rotary atomisation produces an excellent surface finish. The spray has low velocity, which allows the electrostatic forces attracting the paint particles to the ground workpiece to dominate, and results in transfer efficiencies of 85—99%. The pattern is very large and partially controlled and dkected by shaping ak jets. The spray when using a metallic cup has relatively poor penetration into recessed areas. Excessive material deposited on the edges of the workpiece can also be a problem. 

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