Stagnation Conditions

The only way to avert this dilemma is for the community to develop and utilize its capability of forecasting the advent and persistence of the stagnation conditions during which an episode occurs and its capability of computing pollution concentration buildup under stagnation conditions. The details of how these forecasts and computations are made are discussed... 

A survey by national park personnel indicates that large areas of the United States are subject to varying degrees of visibility degradation (1). The middle portion of the eastern half of the country and the Florida Gulf Coast are subject to widespread hazy air masses associated with stagnation conditions. Large portions of the western half of the country are subject... 

Figure 8-2. NsDs diagram for a turbine stage. Efficiency is on a total-to-total basis that is, it is related to inlet and exit stagnation conditions. Diagram values are suitable for machine Reynolds number Re > 10 . (Balje, O.E., A Study of Reynolds Number Effects in Turbomachinery, Journal of Engineering for Power, ASME Trans., Vol. 86, Series A, p. 227.)...

SGo, SLo = entropy at stagnation conditions of vapor and liquid, respectively... 

When gas flows from stagnation conditions through a nozzle, thereby undergoing an isoentropic change, the enthalpy change is represented by Eq. (1.23). The flow velocity is obtained by substitution of Eq. (1.14) into Eq. (1.24) as... 

The incident shock wave moves down the tube, heating and accelerating the test gas. In RST mode, the shock hits an end plate and reflects back to the test gas, further heating the gas and initiating stagnation conditions. Subsequently, a rarefaction wave travels down the tube and quenches all further reactions. 

The simplified ERM is very convenient in that all the properties can be evaluated at the stagnation conditions in the reactor. The method may be appropriate for relief sizing for vapour pressure systems when flow is to be via a safety valve. Discharge coefficients for two-phase flow through safety valves are discussed in 9.7.1. -... 

The ruptured tank had been connected to the cooling tower system that had not been operated since the startup of the biocide system. This stagnated condition and the unusu-ally high ambient temperatures contributed to the explosion. [6]... 

Flow velocities of water in an aquifer, calculated by gradients and transmissivities, provide the maximum possible values. These are subject to limitations imposed by stagnation conditions. In extreme cases, confined systems may be rich in fossil karstic conduits, but with no through-flow due to complete confinement and/or burial beneath the level of the terminal base of drainage. 

A certain nozzle is designed to expand air from stagnation conditions of l. 38 MPa and 200°C to 0.138 MPa. The mass rate of flow is designed to be 4.5 kg/s. Suppose this nozzle is used in conjunction with a blowdown wind-tunnel facility so that the nozzle is suddenly allowed to discharge into a perfectly evacuated tank. What will the temperature of the air in the tank be when the pressure in the tank equals 0.138 MPa Assume that the tank is perfectly insulated and that air behaves as a perfect gas. Assume that the expansion in the nozzle is isentropic. 

With upstream stagnation conditions and (x) given, finite-rate chemistry may influence m by modifying throat conditions. This effect is not addressed here. 

For example, T /T0 = 0.833, p /po = 0.528, and p /po = 0.634 are obtained when y = 1.4. The temperature T0 at the stagnation condition decreases 17 % and the pressure p0 decreases 50% at the nozzle throat. The pressure decrease is more rapid than the temperature decrease when the flow expands through a convergent nozzle. The maximum flow velocity is obtained at the exit of the divergent part of the nozzle. When the pressure at the nozzle exit is vacuum, the maximum velocity is obtained by the use of Eqs. (1.48) and (1.6) as... 

The term /R Tot is proportional to the speed of sound at the inlet stagnation conditions, and is a velocity term. Hence, bearing in mind the definition of the Reynolds number ... 

---