Mass flux maximum

Solution of Eq. (6-114) for G and differentiation with respect to p reveals a maximum mass flux = P2VMJ RT) and a corresponding exit velocity and exit Mach number Mo = L/. This... 

The integration proceeds stepwise until the integral begins to decrease, This occurs at the choked pressure ratio q, giving a maximum mass flux G,9. ... 

Discharge Coefficients and Gas Discharge A compressible fluid, upon discharge from an orifice, accelerates from the puncture point and the cross-sec tional area contracts until it forms a minimum at the vena contracta, If flow is choked, the mass flux G, can be found at the vena contrac ta, since it is a maximum at that point, The mass flux at the orifice is related to the mass flux at the vena contracta by the discharge coefficient, which is the area contraction ratio (A at the vena contracta to Ay at the orifice) ... 

SELF HEAT RATE AT MAXIMUM TEMPERATURE, K/s MASS FLUX PER UNIT AREA, kg/m 2.s ... 

Examination of equation 2.43 shows that the mass flux initially increases as concentration increases but then passes through a maximum and finally declines as velocity decreases due to hindered settling (Figure 2.8). 

In Fig. 2.36 the dimensionless heat flux q is plotted versus the difference (Ti ax — Ts). The dimensionless heat flux is defined as q = [ /(GCpA7 )](7iiax/7iiean), where q is the heat flux, G is the mass flux, Cp is the specific heat, AT Ts — Tja, Ts is the saturation temperature, Tin is the water temperature supplied to the inlet collector, and Tmax and Tmean are maximum and average temperature of the heated surface, respectively. The term qj(GcpAT) reflects the effect of subcooling. 

The heat transfer coefficient of boiling flow through a horizontal rectangular channel with low aspect ratio (0.02-0.1) was studied by Lee and Lee (2001b). The mass flux in these experiments ranged from 50 to 200 kg/m s, maximum heat flux was 15 kW/m, and the quality ranged from 0.15 to 0.75, which corresponds to annular flow. The experimental data showed that under conditions of the given experiment, forced convection plays a dominant role. 

Simultaneous measurements of temporal variations of pressure drop, fluid and heater temperatures show the boiling instability in parallel micro-channels. The channel-to-channel interactions may affect pressure drop between the inlet and the outlet manifold, as well as associated temperature of the fluid in the outlet manifold and the temperature of the heater. The frequency is the same for the pressure drop, the fluid temperature at the outlet manifold, and for the fluctuations of the mean and maximum temperature of the heater. All these fluctuations are in phase. When the heat flux increases, at a constant value of mass flux, the oscillation amplitudes of the pressure drop, the fluid and the heater temperatures also increase. 

It should be noted that the derivative is negative, so that at certain conditions the denominator of Eq. (15-51) can be zero, resulting in an infinite pressure gradient. This condition corresponds to the speed of sound, i.e., choked flow. For a nonflashing liquid and an ideal gas mixture, the corresponding maximum (choked) mass flux G follows directly from the definition of the speed of sound ... 

Search with values of Pi until G is maximized. The choke pressure, PcU is the value of Pi that produces a maximum value of mass flux Gmax. The discharge rate w is given from the mass flux, a discharge coefficient CD, and the orifice cross-sectional area A as... 

Putting 3G/dP2 = 0 to determine the maximum mass flux Gw gives... 

The maximum attainable mass flux for given supply conditions must occur when (// is a maximum. Therefore the pressure P causing the maximum flux can be found by differentiating i//2 with respect to P and equating the result to zero ... 

Results of the model for two parameters, i.e., the spatial temperature profile and the mass flux into the reaction zone as a function of gas mass flux are presented in Fig. 8.7. The temperature profile of the solid fuel flame (Fig. 8.7, left) is similar to that of a premixed laminar flame it consists of a preheat zone and a reaction zone. (The spatial profile of the reaction source term, which is not depicted here, further supports this conclusion.) The temperature in the burnt region (i.e., for large x) increases with the gas mass flux. The solid mass flux (Fig. 8.7, right) initially increases with an increase of the air flow, until a maximum is reached. For higher air flows, it decreases again until the flame is extinguished. 

Figure 22 displays the time-integrated mean of mass flux as function of standard volume flux of primary air for all the three wood fuels, respectively. As indicated by Figure 22, the time-integrated mean of mass flux of conversion gas exhibits a hyperbolic relationship with the volume flux of primary air. In the low range of volume fluxes the conversion gas rate increases up to a maximum. After the maximum point is passed, the mass flux of conversion gas decreases due to convective cooling of the conversion reaction. 

It is evident that m is maximal at M = 1. The maximum mass flux, [rhlA) tained when the cross-sectional area is A as... 

The following processes reduce only the maximum concentration, not the mass flux of disulfoton. 

Opposite to the downward transport of 03s, upward transport of 03t from the troposphere into the stratosphere takes place. This maximizes in summer when deep convective mixing is strongest, concurrent with the maximum photochemical activity. After transport, 03t is chemically destroyed in the stratosphere. We note that reversible cross-tropopause transports of 03s and 03t are not included in the budgets, so Figure 3a and Table 2 represent net mass fluxes. 

At seme critical pressure drop, the mass-flux, w, reaches a maximum value. This takes place at the exit of the straight pipeline and is described by the general set of equations ... 

Since the air pressure decreases with increasing flight altitude, at constant nozzle diameter, the total thrust increases with increasing flight altitude. This increase can correspond to approximately 10 to 30 % of the total thrust depending on the rocket. The maximum thrust is reached in vacuo. The so-called effective ejection velocity ceff (of the combustion gases) is defined as the ratio between the thrust and the mass flux (dm / dt) ... 

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