Static head term

These quantities enable the frictional and accelerative terms in equation 7.83 to be calculated. The static head term can be evaluated by numerical integration using the a—w relationship given in Figure 7.15. 

For small acid gas injection schemes, the reservoir pressure and static head terms are the only ones of significance. In particular, it is assumed that the pressure drop due to friction is not important, although the design engineer is advised to review these factors in each case. Thus equation (9.1) reduces to ... 

EQUATIONS FOR BLOWERS AND COMPRESSORS. Because of the change in density during compressible flow, the integral form of the Bernoulli equation is inadequate. Equation (4.32), however, can be written differentially and used to relate the shaft work to the differential change in pressure head. In blowers and compressors the mechanical, kinetic, and potential energies do not change appreciably, and the velocity and static-head terms can be dropped. Also, on the assumption that the compressor is frictionless, / = 1.0 and hf 0. With these simplifications, Eq. (4.32) becomes... 

The local total pressure drop in a two-phase flow channel is given as sum of three separate components a frictional term, an acceleration term, and a static head term. 

Pressure Drop. The pressure drop across a two-phase suspension is composed of various terms, such as static head, acceleration, and friction losses for both gas and soflds. For most dense fluid-bed appHcations, outside of entrance or exit regimes where the acceleration pressure drop is appreciable, the pressure drop simply results from the static head of soflds. Therefore, the weight of soflds ia the bed divided by the height of soflds gives the apparent density of the fluidized bed, ie... 

As the potential energy term has an essential meaning in hydromechanics, the static head is selected as a comparison quantity. When the energy equation (4.32) is divided by g and integrated, it gives the Bernoulli flow tube equation... 

The terms represent, respectively, the effect of pressure gradient, acceleration, line friction, and potential energy (static head). The effect of fittings, bends, entrance effects, etc., is included in the term Ke correlated as a number of effective velocity heads. The inclination angle 0 is the angle to the horizontal from the elevation of the pipe connection to the vessel to the discharge point. The term bi is the two-phase multiplier that corrects the liquid-phase friction pressure loss to a two-phase pressure loss. Equation (23-39) is written in units of pressure/density. 

Equation 7.10 shows that the total pressure gradient comprises three components that are due to fluid friction, the rate of change of momentum and the static head. The momentum term is usually called the accelerative component. Thus... 

In principle, this is the same as for single-phase flow. For example in steady, fully developed, isothermal flow of an incompressible fluid in a straight pipe of constant cross section, friction has to be overcome as does the static head unless the pipe is horizontal, however there is no change of momentum and consequently the accelerative term is zero. In the case of compressible flow, the gas expands as it flows from high pressure to low pressure and, by continuity, it must accelerate. In Chapter 6 this was noted as an increase in the kinetic energy. 

A centrifugal pump is used to pump a liquid in steady turbulent flow through a smooth pipe from one tank to another. Develop an expression for the system total head A/t in terms of the static heads on the discharge and suction sides zd and zs respectively, the gas pressures above the tanks on the discharge and suction sides Pd and Ps respectively, the liquid density p, the liquid dynamic viscosity p, the gravitational acceleration g, the total equivalent lengths on... 

The term static head generally denotes the pressure in a fluid due to the head of fluid above the point in question. Its magnitude is given by the application of Newton s law (force = mass X acceleration). In the case of liquids (constant density), the static head Pa (Ibf ft ) is given by... 

Figure 6.1 displays a simple flow of fluid in a pipe with all three Bernoulli terms plus the friction factor hL. Please note that here the variable hL represents the friction factor, which is later designated / Why Here hL represents more than / h.L also represents static head and energy grade. Several important concepts are listed ... 

Assuming that oxidation drives the phosphorylation process, thenA) < 0 andX2 > 0, and J U2 is the conventional P/O ratio, while X IX2 is the ratio of phosphate potential to the applied redox potential. The following relations are from Stucki (1980). At static head (sh), analogous to an open circuited cell, the net rate of ATP vanishes, and the rate of oxygen consumption and the force (the phosphate potential) are expressed in terms of a as follows... 

Mitochondrial respiration has certain characteristic states, defined originally by the classical work of Chance and Williams [23]. States 3 and 4 are of particular relevance here. In State 4 the rate of respiration is minimal ( resting state ) due to a maximal back-pressure from the pmf (or from the phosphorylation potential via the pmf). This is a state termed static head in the theory of thermodynamics of irreversible processes (see, e.g., Refs. 24, 25). 

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