Discussion: “The Critical Flow Function for Superheated Steam” (Murdock, J. W., and Bauman, J. M., 1964, ASME J. Basic Eng., 86, pp. 507–516)

1964 ◽  
Vol 86 (3) ◽  
pp. 517-517
Author(s):  
H. V. Beck
Keyword(s):  
Superheated Steam ◽  
Critical Flow ◽  
Flow Function

The Critical Flow Function for Superheated Steam

1964 ◽  
Vol 86 (3) ◽  
pp. 507-516 ◽  
Author(s):  
J. W. Murdock ◽  
J. M. Bauman
Keyword(s):  
Superheated Steam ◽  
Compressibility Factor ◽  
Practical Method ◽  
Ideal Gas ◽  
Critical Flow ◽  
Stagnation Temperature ◽  
Flow Function ◽  
Critical Function ◽  
Inlet Conditions ◽  
Reduced Coordinates

Computations are made of the theoretical critical flow rate of superheated steam through nozzles or other passages. Flow maximization was used in determining the critical function φ=GT11/2/p1. Tabulations of the critical flow function are given for the “superheated vapor” region defined by Keenan and Keyes “Steam Tables” with a pressure limitation of 5000 psia. Two approaches are presented to relate the critical flow function to an ideal state. In the first approach the temperature of the throttled vapor, from inlet conditions, to a very low pressure (p = 0.08854 psia) was used. The second approach utilized the equivalent ideal-gas stagnation temperature that steam would have if its compressibility factor was unity. A dimensionless correlation on reduced coordinates is presented for the second approach, which permits the correlation of steam data to hydrocarbons or other nonideal gases the compressibility factors of which are available as functions of reduced coordinates. A practical method for calculating theoretical critical flow is presented utilizing the properties of steam as taken directly from the Keenan and Keyes “Steam Tables.”

Computation of the Critical Flow Function, Pressure Ratio, and Temperature Ratio for Real Air

1964 ◽  
Vol 86 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Robert M. Reimer
Keyword(s):  
Critical Temperature ◽  
Speed Of Sound ◽  
Critical Pressure ◽  
Pressure Ratio ◽  
Elevated Pressure ◽  
Stagnation Pressure ◽  
Critical Flow ◽  
Stagnation Temperature ◽  
Flow Function ◽  
Temperature Ratio

A method of computing the critical flow function, critical pressure ratio, and critical temperature ratio is presented. Use is made of the NBS Circular 564 tabulated data of the speed of sound, enthalpy, and compressibility. Computations are made for dry real air at stagnation temperature from 60 to 100 F and stagnation pressure from zero to 300 psia. The change in the flow function and ratios is 0.9, 0.5, and 0.4 percent, respectively, over this range. Calculations are also performed at elevated pressure and temperature.

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