Problem Statement

PRODUCT: AFT Arrow

MODEL FILE: AroVerify3.ARO

REFERENCE: Crane Co., Flow of Fluids Through Valves, Fittings, and Pipe, Technical Paper No. 410, Crane Co., Joliet, IL, 1988, Page 4-6, example 4-10

GAS: Steam

ASSUMPTIONS: Example does not specify the heat transfer conditions, so it was assumed adiabatic in this model.

RESULTS:

DISCUSSION:

Crane does not make a distinction between static and stagnation pressure, and it appears that static pressure is usually assumed. Therefore, the inlet pressure of 600 psig was assumed to be static pressure.

To make a one-to-one comparison, the K factors and friction factor used in Crane were used directly in AFT Arrow. The K factors were modeled as fitting and loss values, which evenly spreads the effect of resistance across the entire pipe. In practice, the velocity changes in the pipe can yield different answers for fitting pressure losses depending on where they are actually located.

The AFT Arrow model uses the Redlich-Kwong real gas equation of state for steam. Note that the Crane formula underpredicts the pressure drop (by about 4%), which in most applications is not conservative.

List of All Verification Models