This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
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 =...
View
Full Document
 Spring '11
 Schubring
 Dh, wetted perimeter, Borda–Carnot equation, Friction Factors

Click to edit the document details