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Core and Fuel Assembly Fluid Flow
Published in Robert E. Masterson, Nuclear Reactor Thermal Hydraulics, 2019
where A is the subchannel area away from the wire-wrap, AW is the projected frontal area of the wire-wrap, and KWW is the k factor or “drag coefficient” for the wrap. The k factor is a function of the Reynolds number, and in most correlations, it is a function of the Reynolds number in a reactor coolant channel without a wire-wrap spacer. In most cases, the values of the k factor are smaller than they would be for normal grid spacers. Also, it is easy to see that the k factors are generally lower for a square lattice than they are for a hexagonal one. In some cases, they can be as much as 10%–20% lower. Lenticular wires also have loss coefficients that are about 30% lower than circular wires. In addition to liquid metal fast breeder reactors (LMFBRs), wire-wrap spacers are also used in CANada Deuterium Uranium (or CANDU) reactors (see Figure 18.15).
Lexicon
Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
effective area: (Airflow) The effective area of an outlet or inlet grille or diffuser is the sum of the areas of all the vena contracta existing at the outlet and is affected by (1) the number of orifices and the exact location of the vena contracta and (2) the size and shape of the grille bars, diffuser rings, etc. Manufacturers have conducted airflow tests and based on their findings they have established flow factors or area correction factors for their products. Each flow factor, sometimes called “K-factor” or “Ak,” applies to (1) a specific type and size of grille, register or diffuser, (2) a specific air measuring instrument and (3) the correct positioning of that instrument.
Fluid Mechanics
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
The above equation gives only the theoretical discharge because the loss of energy is not considered. But, in actual practice, there is always some loss of energy as the fluid flows and the actual discharge (Q) will always be less than the theoretical discharge. The actual discharge may be obtained by multiplying the theoretical discharge by a factor Cd, called coefficient of discharge, i.e., Cd=QQth
GreenValve: hydrodynamics and applications of the control valve for energy harvesting
Published in Urban Water Journal, 2018
Stefano Malavasi, Marco Maria Agostino Rossi, Giacomo Ferrarese
Where D is the nominal diameter of the valve expressed in meters. The discharge factor has the same significance of the flow coefficient for a control valve, since they are both expressed as the ratio between the flow rate and the square root of the pressure drop. The discharge factor depends on the regulation of the upstream jet of the turbine and its rotational velocity. However, in this case, the discharge factor varies with the opening degree of GreenValve.