Thermal hydraulics of steam generator sludge
The sludge deposits on top of the tubesheet in commercial steam generators create regions of high susceptibility to tube corrosion. It is believed that the corrosion occurs when the sludge deposit becomes too deep for the liquid to penetrate freely. This leads to liquid deficient regions with high chemical concentrations on the tube surface. A one-dimensional model of two-phase flow in porous media has been developed. The model considers a slab of porous medium on a horizontal non-porous surface, both under water. Heat is transferred from a vertical surface. The vapor, which is generated, flows vertically upward and the liquid is replenished by a counterflow. Under steady state conditions the mass flow rate of liquid equals that of vapor at every point along the flow path. The solution requires a minimum of five equations; continuity and momentum for the liquid and the vapor phases and energy. The momentum equations are extensions of the Darcy equation to the inertial flow regime in porous media. All five equations can be described as first order differential equations. They can be integrated with respect to distance into the sludge pile using the appropriate boundary conditions at the top of the porous slab and the transition point to ``dryout`` or at the bottom of the slab whichever comes first. The conservation of chemical species can be easily incorporated into the above system of equations. A FORTRAN computer program was developed to solve the above set of equations. The solution yields the distribution of the liquid and the vapor velocities and pressures, the heat flux, the liquid saturation and the chemical concentration.
- Research Organization:
- Bettis Atomic Power Lab., West Mifflin, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC11-93PN38195
- OSTI ID:
- 10192899
- Report Number(s):
- WAPD-T-2942; CONF-910739-30; ON: DE94002344; TRN: AHC29314%%3
- Resource Relation:
- Conference: 28. American Society of Mechanical Engineers (ASME) national heat transfer conference,Minneapolis, MN (United States),26-31 Jul 1991; Other Information: PBD: [1991]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
STEAM GENERATORS
SLUDGES
CORROSION
TWO-PHASE FLOW
FOULING
ONE-DIMENSIONAL CALCULATIONS
FLOW MODELS
TUBES
HEAT TRANSFER
POROUS MATERIALS
COMPUTER CALCULATIONS
FLOW RATE
HEAT FLUX
WATER SATURATION
CONCENTRATION RATIO
THERMODYNAMICS
HYDRAULICS
EXPERIMENTAL DATA
200104
COMPONENTS