Pressure loss coefficient

Fig. 7. (a) Configuration for flow turning. The frictional resistance resulting from the bend length must be added (b) pressure—loss coefficient, K, for 90°... 

Liner holes. Liner area to casing area and liner hold area to casing area are important to the performance of combustors. For example, the pressure loss coefficient has a minimum value in the range of 0.6 of the liner area/ casing area ratio with a temperature ratio of 4 1. 

A circular plate of diameter 0.5 m is to be moulded using a sprue gate in its centre. If the melt pressure is 50 MN/m and the pressure loss coefficient is 0.6 estimate the clamping force required. 

The container shown at the top of p. 341 is injection moulded using a gate at point A. If the injection pressure at the nozzle is 140 MN/m and the pressure loss coefficient, m, is 0.5, estimate (i) the flow ratio and (ii) the clamping force needed. 

Equation (14.91) contains only the mass flow ratio /u as a characteristic number of the mechanics of similitude of the mixture. All the other irnpor rant factors, such as particle size, solid density, etc., are contained in the additional pressure-loss coefficient of the solid particles, A, which is determined separately for each material. 

But how can we estimate the pressure-loss coefficient A Stegmaier - has summarized horizontal transport for several fine-granular solids by a correla tion which contains some characteristics of the material. The same idea has been used by Weber, who has found a correlation of the pressure-loss coefficient for vertical pneumatic conveyance based on data measured by Flatow. In order to express these models, we first introduce two dimensiitnless numbers... 

It is known from experience with vertical pneumatic transport that the influence of weight prevails at low velocities, but as the velocity increases friction gains importance. Therefore, in the calculation of the pressure loss one must find not only the weight of the solids, which could be set up theoretically, but also an empirical relationship for vertical transport from the measured data. A correlation of the pressure-loss coefficient for vertical pneumatic conveyance according to data measured by Flatow " has been developed by Weber, and the result is... 

FIGURE M.I3 Pressure-loss coefficient for horizontal transport according to Stegmaier. ... 

FIGURE 14.14 Correiabon of the pressure loss coefficient for vetnca pneumatic conveyance based on Flatow s data according to Weber. ... 

In this chapter the pressure drop for pneumatic conveying pipe flow is studied. The conventional calculation method is based on the use of an additional pressure loss coefficient of the solid particles. The advantage of this classical method is that in principle it can be applied to any type of pneumatic flow. On the other hand, its great disadvantage is that the additional pressure loss coefficient is a complicated function of the density and the velocity of the conveying gas. z lso, it is difficult to illustrate the additional pressure loss coefficient and this makes the theoretical study of it troublesome. 

The new pressure loss equation presented here is based on determining two parameters the velocity difference between gas and conveyed material and the falling velocity of the material. The advantage of this method is that no additional pressure loss coefficient is needed. The two parameters are physically clear and they are quite easily modeled for different cases by theoretical considerations, which makes the method reliable and applicable to various ap>-plications. The new calculation method presented here can be applied to cases where solids are conveyed in an apparently uniform suspension in a so-called lean or dilute-phase flow. 

In addition to the irreversibilities associated with these components, pressure losses (Ap) may occur in various parts of the plant (e.g. in the entry and exit ducting, the combustion chamber, and the heat exchanger). These are usually expressed in terms of non-dimensional pressure loss coefficients, Ap/(p) N, where (/ )in is the pressure at entry to the duct. (Mach numbers are assumed to be low, with static and stagnation pressures and their loss coefficients approximately the same.)... 

Calculation of the specific work and the arbitrary overall efficiency may now be made parallel to the method used for the a/s cycle. The maximum and minimum temperatures are specified, together with compressor and turbine efficiencies. A compressor pressure ratio (r) is selected, and with the pressure loss coefficients specified, the corresponding turbine pressure ratio is obtained. With the compressor exit temperature T2 known and Tt, specified, the temperature change in combustion is also known, and the fuel-air ratio / may then be obtained. Approximate mean values of specific heats are then obtained from Fig. 3.12. Either they may be employed directly, or n and n may be obtained and used. 

The spacer grid in a rod bundle is also a turbulence promoter that enhances liquid-vapor exchange and bubble condensation. The local intensity of such turbulence is a function of the grid pressure loss coefficient, K, and the distance from the grid, t D. Thus an empirical spacer factor, Fs, can be defined as... 

H, p, V = mean values in AZ of enthalpy, density, and velocity, respectively w = flow exchange rate per unit length by mixing Kmz = pressure loss coefficient for channel m in interval Z P = pressure... 

Use of a marching solution to determine the behavior of individual subchannels in an assembly requires that the inlet flow to that assembly be known. The assumption that all assemblies in a core have the same inlet flow can be appreciably in error. Flow must be divided so that the core pressure drop remains essentially constant. Therefore, higher pressure loss coefficients in high-power assemblies, due to the presence of significant exit quality, lead to lower flows in these assemblies. 

Pressure loss coefficient, 13 261 Pressure measurement, 11 783 20 644-665. See also Vacuum measurement electronic sensors, 20 651-657 mechanical gauges, 20 646-651 smart pressure transmitters, 20 663-665 terms related to, 20 644-646 Pressure measurement devices. See also Pressure meters Pressure sensors location of, 20 682 types of, 20 681-682 Pressure meters, 20 651 Pressure microfiltration/ultrafiltration,... 

Where r is the fluid density, u is the mean fluid velocity, and E, is the pressure loss coefficient. The latter coefficient is different for a diffuser and a nozzle, so that the pressure loss depends on the direction of the fluid flow. After a first version... 

HUM Required hot water mass flow rate WA Net turbine shaft work output CR Condenser shell-side pressure loss coefficient X2 Turbine exit quality... 

Ka Pressure loss coefficient through open valves, in/(ft/s)2. 

The pressure loss of randomly packed tubes can be described cither by means of a pressure loss coefficient ( and the pressure drop equation... 

The pressure loss coefficient C (cq. 2) can be determined for typical packing forms, for example, according to [13], A comparison of different catalyst packings with respect to pressure drop is contained in Fig. 7. 

EKf (pipe fittings + valves) is the sum of the pressure loss coefficient for all the fittings and valves in the line. Expressing the maximum fluid rate in pounds per hour, Equation 3-46 becomes... 

FIGURE 17.35 Entrance and exit pressure loss coefficients (a) circular tubes, (b) parallel plates, (c) square passages, and (d) triangular passages [20], For each of these flow passages, the fluid flows perpendicular to the plane of the paper into the flow passages. 

The separator pressure losses are defined as the difference between the sums of static and dynamic pressure before and after the separator. To express the characteristic parameter corresponding to the pressure loss of a separator, the pressure loss coefficient is frequently used where the subscript D is related to the characteristic dimensions of the separator. The pressure loss coefficient depends on the pressure loss of the separator, gravitational acceleration, flow rate gas density and separator dimensions. 

Besides the pressure drop inside the columns there can be an additional pressure loss due to the piping and the valves between the columns. In experiments, a large pressure drop was found in an SMB-SFC apparatus due to these flow resistances [55]. Taking into account the pressure drop as a function of mass flow rates, a pressure-loss coefficient f for the total flow resistance (analogous to pipeline construction) between two columns is determined by fitting to experimental pressure drops. Then the pressure drop can be calculated from ... 

If eight columns are used eight pressure-loss coefficients are needed in total. 9.4.3... 

Pressure loss coefficient through closed valves, in/(fi/s). ... 

The terms in the sum consist of the channel friction factor Xi and the pressure loss coefficient of channel internals or fittings j. For laminar flow in straight channels, the charmel fnction factor Xi is inversely proportional to the Reynolds number in the charmel ... 

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