Effective Area Orifice Elements

(SUB_TYPE)

1: Cd vs. Pressure Ratio element

2: Cd vs. Delta-P element

3: Cd vs. Pressure Parameter element

4: Flow vs. Delta-P element

5: Valve with K-table element

6: Valve with Cd-table element

7: K vs. Reynolds Number element

8: Cd vs. Reynolds Number element

9: Flow vs. Source Pressure element

10: Flow Function vs. Pressure Ratio (Ejector Arm) element

12: Swing Check Valve Element

14: Flow vs. Sink Static Pressure

15: Flow vs. Sink Total Pressure

16: Flow vs. Delta-P vs. T element

17: Louver element

18: Flow vs Source Pressure vs. Sink Static Pressure

Flow is calculated based on an effective orifice area of (AREA* CD) with CD evaluated from the table of curves according to the subtype.

It is recommended that AREA represent physical area and CD range from zero to one.

Valve modeling should use a physical area based on valve position rather than the full open area.

If the element is rotating or directly connected to one or more rotating elements, the reference direction is defined as parallel to the engine centerline and the angle is the projected angle in the tangential direction. Otherwise, the reference direction is arbitrary but assumed to be the same as the reference direction for all other elements attached to the upstream chamber.

THETA for an element downstream of a plenum chamber has no impact on the solution except to set the default value of THETA_EX.

(See also THETA_EX)

PHI for an element downstream of a plenum chamber has no impact on the solution except to set the default value of PHI_EX.

(See also PHI_EX)

(Do not use zero unless the orifice is not rotating)

(RPMSEL)

0.0: Specifies a stationary element.

1.0: Points to general data ELERPM(1).

2.0: Points to general data ELERPM(2).

3.0: Points to general data ELERPM(3).

-1.0: Element RPM is based on upstream fluid RPM.

See Element Heat Addition for more information.

If DQ_IN > 0 and the upstream chamber has a positive component of relative velocity aligned with the centerline of the orifice, the driving pressure is reduced by the equation:

${Pt}_{upstream}={Ps}_{upstream}+\left(1.0-D{Q}_{IN}\right)*({Pt}_{upstrea{m}_{no}-loss}-{Ps}_{upstream}$

(Default value = 0)

Axial (K_EXIT_Z)

Tangential (K_EXIT_U)

Radial (K_EXIT_R)

Refer to the General solver theory sections for more details about this input.

THETA_EX is an optional variable to be used if the orientation of the element exit differs from that of the element inlet.

The default value (THETA_EX = -999) results in the assumption that THETA_EX = THETA.

Other values are interpreted in the manner presented in the description of THETA.

PHI_EX is an optional variable to be used if the orientation of the element exit differs from that of the element inlet.

The default (PHI_EX = -999) results in the assumption that PHI_EX = PHI.

Other values are interpreted in the manner presented in the description of PHI.

(HYDDIAM)

0: Standard Compressible Flow

3: Incompressible Liquid

10: Auto Detect fluid type based on fluid in upstream chamber.

If the value is 0.0, exit conditions are only based on the orifice mechanical area and losses associated with the orifice.

(VALVE_POS)

Used with subtype Valve with K-table and Valve with Cd-table.

<0 : CD_REV is really a K loss value, CD=1/sqrt(K+1)

0 :CD_REV is the same as CD (forward)

>0 and <1: CD_REV is the CD to use for reversed flow.

4: Check valve, do not allow any reversed flow.

5: Use negative part of table. Table is expected to have values to use for negative flow. This could be negative Delta P or pressure ratios < 1.

(MASS_OR_VOL)

0: flow provided in lbm/sec

1: Flow provided in Gallons per Minute

5: Flow Provided in a Standard Gallons per minute.

${Vol\_flow}_{act}={Vol\_flow}_{std}*\frac{P_{std}}{P_{upstream}}*\frac{T_{upstream}}{T_{std}}$

-2 or 0: Fully opened

>1 : Partially open

(HEAT_MODE)

See Element Heat Addition for more information.

See Element Heat Addition for more information.

(P_STD)

(T_STD)

(Usually, an echo of the user input unless modified inside Flow Simulator.)

Tangential (K_EXIT_U)

Radial (K_EXIT_R)

(Usually, an echo of the user input unless modified inside Flow Simulator.)

(Usually an echo of the user input but converted to radians.)

(Usually an echo of the user input but converted to radians.)

(Usually, an echo of the user input unless modified inside Flow Simulator.)

(Usually, an echo of the user input unless modified inside Flow Simulator.)

(Usually, an echo of the user input unless modified inside Flow Simulator.)

(Usually an echo of the user input unless modified inside Flow Simulator.)

Calculated from the discharge coefficient using equation.

(Output is an echo of the user input.)

Limited by critical pressure ratio for supersonic flows.

Positive values indicate heat added to the fluid; negative values indicate heat removed.