WSeal Element

WSeal Element General Description and Quick Guide

Flow Simulator WSeal element models the leakage flow across the W-Seal. This can be used only in Compressible (e.g. gas systems) analysis.

WSeal Element Inputs

Table of the inputs for the WSeal Element.

Element Specific W Seal Input Variables
Index UI Name (. flo label) Description
1 No. of. Convolutions (NOC) Number of Convolutions
2 Youngs Modulus Youngs Modulus of WSeal Material
3 Pitch Radius Pitch Radius measured from Engine centerline
4 Initial Compression Initial Compression
5 Compression Model
  1. Off
  2. On
6 Load (Deflection Based) Load Acting on WSeal (Needed only when Compression model == ON)

WSeal Element Theory Manual

Nomenclature:
: Mass flow rate Specific heat Ratio
Tt: Total Temperature R: Gas Constant
Pt: Total pressure Ts: Static Temperature
Ps: Static pressure Density
gc: Gravitational Constant
Subscripts:
in: Upstream station ex: Downstream station

W seal element solves the flow rate based on cross-sectional area and losses provided from user input.

If Compression if off, then

If Compression is on, then the calculated compression is based on number of convolutions

Number of Convolutions K_emp Calculations
1
2
3
4

Now the effective Clearance is computed by the following formula

Mass flow rate is calculated by Flow Function equation,

For Choked Condition

WSeal Element Outputs

The following listing provides details about WSeal Element output variables.

Element Specific W Seal Output Variables
Index Field Description Units
1 No.of. Convolutions Number of Convolutions (User Input) Unitless
2 Youngs Modulus Youngs Modulus of WSeal Material (User Input) Psi, mPa
3 Pitch Radius Pitch Radius measured from Engine centerline (User Input) in, m
4 Initial Compression Initial Compression (User Input) in, mm
5 Compression Model
  1. Off
  • On

(User Input)
6 Load (Deflection Based) Load Acting on WSeal (Needed only when Compression model= ON) (User Input) lbf, N
7 Flow Regime If Chocked flow
8 Calc Compression Calculated Compression if Compression model = ON in, mm
9 Total Compression Initial Compression + Calc Compression in, mm
10 Effective Clearance Clearance computed in, mm
11 Leakage Area Leakage Area in2 , m2
12 Leakage Flow Mass flow rate Lbm/s, kg/s
13 VEX Exit Velocity ft/s, m/s
14 MACHEX (EXMN) Exit Mach number Unitless
15 PTS Total Pressure Upstream psi, mPa
16 PSEB Static Pressure Downstream psi, mPa
17 PTEX Total Pressure Downstream psi, mPa
18 TTS Total Temperature Upstream F, K
19 TTEX Total Temperature Downstream F, K
20 RHO Density lb/in3, kg/m3
21 Gamma Gamma Unitless

References

  1. Neelesh, S., Wolfe, C., Sezer, I., Ziegler, R., Chupp, R., “Chaterterization of metallic W-seals for inner to outer shroud sealing in industrial gas turbines”, Proc. ASME Turbo Expo 2012, GT2012-68131.
  2. Neelesh, S., “ Characterization of Metallic W Seals for Inner Shroud to Outer Shroud Sealing”, GRC-TISCAT report - 2010GRC861.
  3. Farahani, A., Childs, P., “Nozzle guide vane static strip seals”, Proc. ASME Turbo Expo 2006, GT2006-90185.
  4. Farahani A., Childs, P., “Characterization of static strip Seal flow”, Proc. ASME Turbo Expo 2007, GT2007-27469.
  5. Farahani, A., Childs, P., “Validation and comparison of strip seal design for gas turbine engine nozzle guide vanes”, Proc. 2008 ASME IMECE2008-68311.
  6. Ludwig, L., P., Johnson, R., L., “Sealing technology of aircraft gas turbine engines”, NASA Technical Memorandum -TM X-71607.
  7. “Seal Technology in Gas Turbine Engines”, AGARD Conference Proc – 237.
  8. Steinetz, M., Bruce, “Seal Technology”, Mechanical Engineers handbook – Materials and Mechanical design, Volume 1, Third Edition.
  9. Bill, C., Robert, “Wear of Seal Materials used in Aircraft Propulsion Systems”, Wear, 59 (1980) 168-189.
  10. http://www.nicholsons.com/pdf/E-Seals.pdf, Nicholsons Seals.
  11. http:/www.eaton.com/ecm , “Resilient Seals”, EATON’S Aerospace, TF100-35C_Resilient Seals.