Flux per unit area

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

Radiant flux per unit area incident on a surface. 

J+,./ = flux per unit area of cationic and anionic species, respectively... 

Figure 5.7. Solids flux per unit area as a function of volumetric concentration...

Now it is important to stress that, whereas the laminar flame speed is a unique thermochemical property of a fuel-oxidizer mixture ratio, a turbulent flame speed is a function not only of the fuel-oxidizer mixture ratio, but also of the flow characteristics and experimental configuration. Thus, one encounters great difficulty in correlating the experimental data of various investigators. In a sense, there is no flame speed in a turbulent stream. Essentially, as a flow field is made turbulent for a given experimental configuration, the mass consumption rate (and hence the rate of energy release) of the fuel-oxidizer mixture increases. Therefore, some researchers have found it convenient to define a turbulent flame speed, S T as the mean mass flux per unit area (in a... 

In order to see why these conflicts arise, we consider a flux / per unit area per unit time of X-ray photons incident on a detector of efficiency. The number of photons N detected in an integration time in a square picture element of side is then... 

The incident heat flux per unit area to the personnel can now be calculated [Equations (5-19) and (5-20)] as ... 

With the energy hv = he/Xq of each photon, the energy flux per unit area is given by... 

Since /, the intensity of radiation is the energy flux per unit area per unit time, it is related to the radiation density p(v m) by the factor c, the velocity of light ... 

Recall the distinction between advective and diffusive transport, which we made in Section 18.1 while traveling in the dining car through the Swiss Alps. We then introduced Fick s first law to describe the mass flux per unit area and time by diffusion or by any other random process (Eq. 18-6). Rewritten in terms of partial derivatives, the diffusive flux along the x-axis is ... 

The corresponding particle mass flux per unit area through any horizontal cross section is ... 

In the absence of any subsurface source or sink of water, the law of mass conservation applied to the water itself requires the remaining integral in Eq. 23-14 to be zero. Thus, in spite of the water currents, the mean flux per unit area at z0, Fs = Fs / A0, looks like the flux in a quiescent water body (Eq. 23-12). 

At steady state there will be a linear concentration profile of solute across the center fluid region. The concentration gradient dC/dz will be AC/a. In addition there will be a flux of solute species across the fluid from the high-concentration boundary (z = a) to the low-concentration boundary. The flux of species will be proportional to the areas of the bounding walls, proportional to the concentration difference AC, and inversely proportional to the gap distance a. The molar flux per unit area is thus... 

Referring to Figure 2.4, one can see that as long as JX2 Ax/2it = Jx2+ax/2,p the concentration of material bounded by the walls of unit cross-sectional area at (x2 Ax/2) will be time invariant. On the other hand, if JXj Ax/2t > JXj+ax/2,p a net increase of material into the box would be expected, and concentration would increase with time. Since J is defined as the flux per unit area, dividing J by the distance between the walls yields the time rate of change of concentration within the box. More formally,... 

Here, in addition to the usual notations, D for the detonation velocity, u for the velocity of the material (both are measured with respect to the unreacted, unperturbed fresh mixture), p for the pressure, v for the specific volume (in cm3/g), and I for the enthalpy of a unit mass, we have also introduced the following quantities M for the mass flux per unit area of a surface moving at the detonation velocity6 (in g/cm3 sec this quantity is equal to the mass velocity of combustion), F for the braking force per unit... 

Figure 7.13 shows the different contributions on the anodic side. The heat fluxes per unit area for a tubular cell 1.5 m long are shown. The total contribution due to convection is about 35%. The convective heat flux decreases along the cell mainly... 

Equation 6.8 demonstrates that the energy flux per unit area and unit time depends only on the square of the amplitude and the speed of light. 

Here ft is the solid angle of the radiation and evis a spectral energy flux per unit area per unit frequency. 

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