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Unformatted text preview: Applications in Nuclear Systems April 19, 2011 Nuclear Application Topics I Variable properties and acceleration pressure loss I Computation of friction factors I Minor losses, including pressure loss at spacers In these slides (this course), assume singlephase conditions throughout. Variable Properties Primarily due to heating (change in temperature), water in a PWR does not have the same properties throughout the core. Typically, density decreases in the direction of flow by about 10%. As a result, both gravitational and frictional pressure loss are best estimated by an integral: Δ P fric = Z L 2 L 2 ρ ( z ) gdz (1) Δ P fric = Z L 2 L 2 f ( z ) 1 D h ρ ( z ) V ( z ) 2 2 dz (2) However, the product ρ ( z ) V ( z ) is not a function of z . G = ˙ m / A . Δ P fric = G 2 Z L 2 L 2 f ( z ) 1 2 ρ ( z ) D h dz (3) Variable Properties (2) In a PWR, the system parameters can often be estimated by use of properties at the midplane. Δ P fric = G 2 f mp L 2 ρ mp D h dz (4) An additional term (acceleration pressure drop) must be considered in the case of variable properties. In general: Δ p accel = ρ out v 2 out ρ in v 2 in (5) Change in density, constant area Δ p accel =...
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This note was uploaded on 07/14/2011 for the course ENU 4133 taught by Professor Schubring during the Spring '11 term at University of Florida.
 Spring '11
 Schubring

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