Spiralc
Computational Analysis of Spirally Grooved Gas Face Seals
COST: $5,000 Executable + GUI (2012)
SPIRAL
GROOVE FACE SEAL OPERATION
Spiral
groove face seals (SGFS) offer numerous advantages over conventional non
contacting mechanical seals. Grooves etched on the mating ring of the sealing
surfaces do not wear from contact while rotating, greatly lessening the need to
overhaul machines for seal replacement. Dry (gas lubricated) operation allows
the face seal to perform with less complicated and expensive external support
systems like those required for oil lubricated seals. The use of tandem and
double sealing arrangements with inert buffer gases allow application of the
SGFS in machines handling highly volatile process fluids with virtually zero
leakage to the atmosphere.
METHOD
of ANALYSIS
The
laminar flow of an isothermal, ideal gas on the thin film lands of a grooved
face seal is described by the Reynolds equation for isoviscous fluids (no fluid
inertia effects) where a successive approximation allows solution of the
nonlinear flow equation.
The zerothorder equation describes the fluid flow
field for a rotor static equilibrium position providing the leakage flow rate,
load capacity and drag torque, while the firstorder equations govern the fluid
flow for small amplitude axial motions determining the force coefficients due
to rotor axial motions.
Numerical
Method of Solution: Finite Elements
PROGRAM
FEATURES
The program calculates the
static load and dynamic axial force coefficients for gas spiral grooved face
seals (SGFSs).
Configurations: Grooved
stationary or rotating surface. Seal dams inside the
Geometry: (See Figures
1.) I.D., O.D., grooved ID, grooved O.D., ridge clearance, groove depth
Number
of grooves: 1 < N_{g} < 30
(a) 
(b) 

Ridge
width ratio:
Groove
(helix) angle: (Radial grooves b = 90°)
Specified
Boundary conditions: I.D. Pressure & O.D. Pressure, or no I.D. flow (thrust
bearing).
Fluid: Viscosity,
density
Spiral calculates:
Limitations
and Restrictions:
Laminar,
isothermal flow with isoviscous, compressible fluids without fluid inertia
effects
PROGRAM
OPERATION
Input: ExcelŽ GUI
Output: ExcelŽ GUI
Language: Fortran90.
Source code NOT provided.