Total energy flow

The amount of heat actually taken up by the particles was an important quantity, as tubes operate under heat transfer limited conditions near the tube inlet. Fig. 30 shows a plot of Q against r, where Q was the total energy flow into the solid particles, for the entire segment. For inlet conditions, Q varied strongly at lower r, but was almost constant at higher values. As rcut/rp decreased from 0.95 to 0.0 and the effectiveness factor increased from nearly zero to one, the active solid volume increased by a factor of 7. If the solid temperature had remained the same, the heat sink would also have had to increase sevenfold. This could not be sustained by the heat transfer rate to the particles, so the particle temperature had to decrease. This reduced the heat sink and increased the driving force for heat transfer until a balance was found, which is represented by the curve for the inlet in Fig. 30. 

To summarize the total energy flow in space surrounding the conductors has two components as follows ... 

Heat can be defined as a portion of the total energy flow across a system boundary and is caused by a temperature difference between the system and the surroundings. Heat can be exchanged by conduction, convection and/or radiation. We can evaluate heat transfer by use of the energy balance, which will be discussed later. 

In Chapter 5, we used an approach based on microscopic velocity distributions to investigate the ideal gas pressure difference established between two chambers held at different temperatures at steady state. The chambers were separated by a partition containing a hole small enough that effusive flow existed between the chambers. We will now apply steady-state thermodynamics to the same system. Because, in Eq. (62) of Chapter 5, we calculated the total energy flow between the... 

Example 7.3 Total energy flow and phenomenological equations For mixtures, the energy flow contains the conductive flow qc, and the contributions resulting from the interdiffusion q, of various substances and the Dufour effect q we therefore express the total energy flow relative to the mass-average velocity... 

For example, the total energy flow of electromagnetic field through the surface Si of the domain Vi, containing domain Q (Figure 8-1), is equal to... 

The total energy flow of the residual field through the earth s surface (z = 0), is calculated by the formula... 

Table 5 Effect of the moisture content on the parameters of the symmetric logistic function adjusted to the total energy flows of carbonization.

The mean values of the parameters of the symmetric logistic function are given in table 6. We have identified significant effects of the shape and the species on factor a and b of the total energy production, as well as a significant interaction between shape and species. Blocks 16 of poplar are characterized by a total energy flow delayed and slowed down compared to other wood samples. 

The factor a is significantly influenced by the species and the shape of wood samples. Total energy flows are delayed for poplar in comparison with beech and for blocks 16 in comparison with cubes 4. However, there is no significant effect on factor b nor significant interaction. 

Calculate the total mass flow in Ib/h and the total energy flow in Btu/h at both the entrance and exit of the boiler. 

The total energy flow along the jets to infinity is given by... 

Work. The total energy flow into the system due to work will be divided into several parts. The first part, called shaft work and denoted by the symbol Wj, is the mechanical energy flow that occurs without a deformation of the system boundaries. For example. 

Since this work is done on the system, it enters the energy balance as a positive quantity. Therefore the total energy flow into the system due to mass flow is as follows ... 

Example 7,5 Total energy flow and phenomenological equations... 

Thus, (2.5) provides a ranking of all k elements relative to the total energy flowing through all the elements in the system. It is proposed that an element with a low activity index has a small contribution to the system dynamic response, thus it is unnecessary under the given scenario and, therefore, can be eliminated from the model to generate a reduced model. This elimination procedure is described in Section 2.3. 

The above theorem, like all those which have appeared so far, is based on the supposition that there is no exchange of matter between the bodies. If such an exchange takes place the notion of heat flow becomes ambiguous cmd we ean speak only of the total energy flow. 

An alternative approach is shown in Figure 6.7. The two fuel flow measurements are summed, with suitable scaling factors to ensure the result is in units consistent with the total energy supplied. The result is then used as the PV of a total energy flow controller. 

In many practical problems, these three mechanisms combine to generate the total energy flow. 

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