Pressure static head term

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... 

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... 

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). 

The pressure at Pj is now the 1-psi static head minus the 5-psi nozzle exit loss or negative 4 psig (or positive 10.7 psia). That is, the pressure at the drain is a substantial partial vacuum, or a negative pressure. By the term negative pressure I mean that it is below atmospheric pressure (atmospheric pressure at sea level is 16.7 psia). 

The term static head generally means the pressure of a fluid exerted by the head of a fluid above the point in question. 

Although the term static pressure is generally used in designing fen and duct systems and is the performance quoted hy fen manufacturers in tables and charts, the total pressure of the system is a characteristic for which the total mechanical energy must he supplied for the system. Note that when the velocity in a duct remains constant, the velocity head remains constant... 

The term (z - 2i) may be called a static pressure head, and it can be expressed in feet or inches of water, or some height of any liquid. For example, barometric pressure can be expressed in inches of mercury. 

The DPAT variable is found by applying Eq. (5.48), the static pressure loss per tube row, a key equation that is to be experimentally determined. The last term, u2/2g, is the velocity head energy of the fan required to move the required airflow through the air cooler. As the air is heated while passing through the fin tubes, it expands, causing an increase in velocity. The air velocity difference, (v2 - iq)2, is the velocity head in the Bernoulli equation. 

Ii the analysis of piping systems, pressure losses are commonly expressed in terms of the equivalent fiiid column height, called the head loss / ,. Noting from fluid statics that AP = pgh and thus a pressure difference of AP corresponds to a fluid height of h = Plpg, the pipe head loss is obtained by dividing APt by pg to give... 

FIGURE 3-5 Under static conditions (no water movement), hydraulic head in a continuous volume of water is constant throughout and is equal to the sum of the elevation term and the pressure term. Decreasing the elevation relative to the reference elevation by an amount Az increases water pressure by an amount equal to pgA therefore, the decrease in the elevation term exactly offsets the increase in the pressure term, and the hydraulic head is unchanged. 

The first, second, and third terms in Equation 3-2 represent pressure head, velocity head, and static differences respectively. Equation 3-2 is used for investigating energy distributions or determining pressure differentials between any two points in a pipeline. Incorporating the head loss due to friction, hL, with constant pipe diameter, i.e., V, = V2, Equation 3-2 becomes... 

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