Elevation Element
Elevation Element General Description & Quick Guide
Elevation Element (gravitational orifice) is similar to Orifice element is used to calculate orifice flow including the effect of gravity and rotation. Elevation Element uses an input of Orifice mechanical Area/Diameter & Loss parameters and Gravitational effects (Inlet & Exit Heights). Loss Parameter can be Cd (Coefficient of discharge) or Incompressible Loss Coefficient (K). Elevation element can be found under both “Compressible Gas Elements” & “Incompressible Liquid Elements” section.
Elevation Element Inputs
Table of the inputs for the Elevation Element.
Element Specific Conventional Orifice Element Input Variables  
Index  UI Name (. flo label)  Description 
1  CrossSection Shape (CS_SHAPE) 
Crosssection shape allows user to specify geometry in three different ways; (1): Area is not set (1): Arbitrary shape with Area (2): Circular with Diameter 
2  Exit Area (EXIT_AREA) 
User defined exit area used to calculate exit conditions. Required if CS_SHAPE flag is 1. 
3  Exit Diameter (EXIT_DIAM) 
User defined exit diameter of elevation element used to calculate exit conditions. Required if CS_SHAPE flag is 2. 
4  Loss Mode (LOSS_MODE) 
Loss mode type flag: (1): Cd – Compressible Loss Coefficient (2): K – Incompressible Loss Coefficient 
5 
Cd – Compressible Loss Coefficient Or K – Incompressible Loss Coefficient 
Cd or KLoss Value. Input Limits: 0 < CD < 1 K>0 
6  Rotor Index (RPMSEL) 
Reference rotor index for usersupplied swirl. Stationary (Database Value = 0.0) Rotor 1 (Database Value = 1.0): Points to general data Shaft 1 Rotor Speed. Rotor 2 (Database Value = 2.0): Points to general data Shaft 2 Rotor Speed Rotor 3 (Database Value = 3.0): Points to general data Shaft 3 Rotor Speed Rotates with Air (database Value = 1.0): Element RPM is based on upstream fluid RPM 
7  Inlet Radius (INLET_RADIUS) 
Radial distance between the orifice inlet center and the engine centerline. (Do not use zero unless the orifice is not rotating) 
8  Exit Radius (EXIT_RADIUS) 
Radial distance between the orifice inlet center and the engine centerline. (Do not use zero unless the orifice is not rotating) 
9  Inlet Height (INLET_HEIGHT)  Inlet elevation to be used in pressure correction calculations 
10  Exit Height (EXIT_HEIGHT)  Exit elevation to be used in pressure correction calculations 
11  Portion of Ustrm Chamb. Dyn. Head Lost (DQ_IN)  Inlet dynamic head loss. Refer General solver theory sections for more details about this input 
12  Gravity Multiplier (GRAV_MULT)  Gravity multiplier 
13  Element Inlet Orientation: Tangential Angle (THETA) 
Angle between the element centerline at the entrance of the element and the reference direction. 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) 
14  Element Inlet Orientation: Radial Angle (PHI) 
Angle between the element centerline at the entrance of the element and the THETA direction. (spherical coordinate system)
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) 
15 
Exit K Loss: Axial (K_EXIT_Z) Tangential (K_EXIT_U) Radial (K_EXIT_R) 
Head loss factors in the Z, U, and R directions based on the spherical coordinate system of theta and phi. (Default value provides no loss).
Refer General solver theory sections for more details about this input 
16  Element Exit Orientation: Tangential Angle (THETA_EX) 
Angle between the orifice exit centerline and the reference direction. 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) will result in the assumption that THETA_EX = THETA.
Other values will be interpreted in the manner presented in the description of THETA. 
17  Element Exit Orientation: Radial Angle (PHI_EX) 
Angle between the orifice exit centerline and the THETA_EX direction.
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) will result in the assumption that PHI_EX = PHI.
Other values will be interpreted in the manner presented in the description of PHI. 
18  Heat Addition Mode (HEAT_MODE) 
This tells the solver how to interpret QINHEAT. 0: Adiabatic 1: Heat addition 2: Head addition proportional to element mass flow rate 3: Delta Total temperature 4: Fixed Fluid Total temperature at exit 
19  Heat Added (QINHEAT) 
Heat Added – if Heat Mode =1 or 2 Delta.T – if Heat Mode =3 Fixed total temperature at exit = 4 
20  Fluid Compressibility Mode (FLUID_MODE) 
The user can choose which solution algorithm to use. 1: Compressible Gas 2: Incompressible Gas 3: Incompressible liquid 
Elevation Element Theory Manual
The flow function written to define the flow through an elevation element in terms of upstream total pressure, upstream total temperature, downstream static pressure and crosssectional flow area. Since the flow function is derived with the assumption of isentropic flow, some sort of empirical correction is required to account for the irreversible losses encountered in the Orifices. This is usually contained in form of a discharge coefficient or Loss coefficient, included in the working definition of flow function and represents the ratio of actual (empirical) to ideal (isentropic) flow rates.
Nomenclature:  
W: Mass flow rate  : Specific heat Ratio 
A: Orifice mechanical area  R: Gas Constant 
CD: Coefficient of Discharge  Ts: Static Temperature 
K: Incompressible Loss Coefficient  : Density 
Tt: Total Temperature  MN: Vena Contracta Mach Number 
Pt: Total pressure  Cp: Specific Heat 
Ps: Static pressure 
gc: Gravitational Constant JLC = 778.169 
Discharge Loss Coefficient Calculations
Loss Mode: Cd – Compressible Loss Coefficient
Loss Mode: K – Incompressible Loss Coefficient
Flow Rate Calculations
These equations can be used to derive an expression for mass flow rate, .
In the above equations, the corrected pressures (for the effects of Gravity & Pumping) will be used, which are defined below
Compressible and Incompressible Gas Conditions:
Inlet Conditions:
Exit Conditions:
Incompressible Liquid Conditions:
Inlet Conditions:
Exit Conditions:
Elevation Element Outputs
The following listing provides details about conventional orifice output variables.
Name  Description  Units 

FLOWS: FLOW: %WREF & MASSFLOWRATE 
Flow rates in %WREF and [PPS]or [kg/s]  (None) & (PPS or kg/s) 
SOLVER_STAT  Information on status of the elevation element solution  Flag 
FLUID:  Fluid equation type information  Flag 
CHOKED_FLOW_SOLVER_STAT  Convergency information  Flag 
NEWTON_ITERS:  How many iterations before nonconvergence  Flag 
ERROR:  Error value if the solver does not converge to solve elevation element  Unitless 
DQ_IN 
Portion of Ustrm Chamb. Dyn. Head Lost (Usually an echo of the user input unless modified inside Flow Simulator.) 
Flag 
Axial (K_EXIT_Z) Tangential (K_EXIT_U) Radial (K_EXIT_R) 
Exit K Loss (Usually an echo of the user input unless modified inside Flow Simulator.)

Unitless 
ELEMENT_THETA 
Tangential Angle (Usually an echo of the user input but converted to radians.) 
radians 
ELEMENT_PHI 
Radial Angle (Usually an echo of the user input but converted to radians.) 
radians 
REL_INLET_ANGLE  It is a relative inlet angle calculated based on upstream chamber velocity  Deg 
ELEMENT_RPM 
RPM (Rotor index) (Usually an echo of the user input unless modified inside Flow Simulator.) 
rad/min 
RIN 
Radius (Usually an echo of the user input unless modified inside Flow Simulator.) 
in, m 
REX 
Radius (Usually an echo of the user input unless modified inside Flow Simulator.) 
in, m 
GRAV_MULT  Gravity Multiplier  
INLET_HEIGHT 
Inlet Height (Usually an echo of the user input unless modified inside Flow Simulator.) 
in,m 
EXIT_HEIGHT 
Exit Height (Usually an echo of the user input unless modified inside Flow Simulator.) 
in,m 
ELEMENT_AREA 
Crosssectional area. (Usually an echo of the user input unless modified inside Flow Simulator.) 
inch^{2}, m^{2} 
CD 
Discharge coefficient. (Usually an echo of the user input unless modified inside Flow Simulator.) 
(fraction) 
K 
Head loss coefficient. Calculated from the discharge coefficient using equation 
(unitless) 
EXIT_AREA 
Exit area used for calculating exit conditions of the orifice element. This output is only printed when an exit area is used (EXIT_AREA>0). A default value of 0 has no effect on exit conditions. (Output is an echo of the user input.) 
inch^{2}, m^{2} 
PTS  Driving pressure relative to the rotational reference frame (i.e. rotor) at the restriction inlet.  psi, mPa 
PTEX  Total pressure relative to the rotational reference frame (i.e. rotor) at the restriction exit including supersonic effects.  psi, mPa 
PSEX 
Static pressure relative to the rotational reference frame (i.e. rotor) at the restriction exit. Limited by critical pressure ratio for supersonic flows. 
psi, mPa 
PSEB  Effective sink (static) pressure downstream of the restriction.  psi, mPa 
TTS  Total temperature of fluid relative to the rotational reference frame (i.e. rotor) at the restriction inlet.  deg F, K 
VCMN  Fluid Mach number relative to the rotational reference frame (i.e. rotor) at the vena contracta.  (unitless) 
VXA  Fluid velocity relative to the rotational reference frame (i.e. rotor) at the restriction exit before heat input (QIN) effects.  ft/s, m/s 
EXMN  Fluid Mach number relative to the rotational reference frame (i.e. rotor) at the restriction exit before heat input (QIN) effects.  (unitless) 
QIN 
Heat input. Positive values indicate heat added to the fluid; negative values indicate heat removed. 
BTU/s, W 
DT  Change in total temperature relative to the rotational reference frame (i.e. rotor) due to heat input (QIN).  deg F, K 
TEX  Total temperature relative to the rotational reference frame (i.e. rotor) at the restriction exit.  deg F, K 
VEX  Fluid velocity relative to the rotational reference frame (i.e. rotor) at the restriction exit including heat input (QIN) effects.  ft/s, m/s 
VABS  Magnitude of the fluid total absolute velocity  ft/s, m/s 
VTAN_ABS  Magnitude of the fluid absolute tangential velocity  ft/s, m/s 
VAXIAL  Magnitude of the fluid axial velocity  ft/s, m/s 
VRAD  Magnitude of the fluid radial velocity  ft/s, m/s 
THTA_ABS  Fluid absolute tangential flow angle  rad 
VREL  Magnitude of the fluid total velocity relative to the element  ft/s, m/s 
VTAN_REF  Reference frame tangential velocity  ft/s, m/s 
VTAN_REL  Magnitude of the fluid tangential velocity relative to the element  ft/s, m/s 
VNORM  Magnitude of the fluid total velocity relative to the element  ft/s, m/s 
THTA_REL  Fluid relative tangential flow angle  rad 
TTABS  Absolute total temperature  deg F, K 
TTREL  Relative total temperature  deg F, K 