Meco Solids

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Revision as of 21:20, 7 July 2025 by Admin (talk | contribs) (Created page with "= Meco Solids = Solid components model heat transfer through solid materials in rocket engine systems. They are essential for thermal analysis of combustion chambers, nozzles, and cooling systems. == Overview == The Meco Rocket Simulator supports 1 solid component type: {| class="wikitable" |- ! Component Type !! Purpose !! Key Features !! Applications |- | Solid || Heat transfer modeling || Multi-layer thermal analysis || Chamber walls, cooling channels, nozzles |}...")
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Meco Solids

Solid components model heat transfer through solid materials in rocket engine systems. They are essential for thermal analysis of combustion chambers, nozzles, and cooling systems.

Overview

The Meco Rocket Simulator supports 1 solid component type:

Component Type Purpose Key Features Applications
Solid Heat transfer modeling Multi-layer thermal analysis Chamber walls, cooling channels, nozzles

Solid Component

Overview

  • Type: Solid
  • Purpose: Heat transfer solid for modeling chamber walls, cooling channels, and thermal barriers
  • Modeling: Multi-dimensional heat conduction with boundary conditions from gas and liquid flows

Parameters

Basic Parameters

  • Connection Parameters:
    • name - Component name (string)
    • branch_gas - Connected gas branch name (string)
    • branch_liquid - Connected liquid branch name (string)
  • Material Properties:
    • materialName - Material type identifier (string)

Thermal Parameters

  • Wall Properties:
    • wallDelta - Wall thickness in meters (double)
    • wallDeltaSubdivisions - Number of subdivisions through thickness (size_t)
    • wallInitialT - Initial temperature in Kelvin (double)
  • Geometric Parameters:
    • chamberCriticalRadius - Critical radius in meters (double)
    • chamberThroatCurvatureRadius - Throat curvature radius in meters (double)
    • coolingChannelLandX - Cooling channel land dimension in meters (double)

Design Guidelines

Material Selection

Common rocket engine materials:

  • Copper: Excellent thermal conductivity, regenerative cooling
  • Stainless Steel: Good strength, moderate thermal properties
  • Inconel: High-temperature strength, gas generator applications
  • Carbon-Carbon: Ultra-high temperature, nozzle extensions
  • Ceramic: Thermal barrier coatings, insulation

Thermal Mesh Resolution

  • Subdivisions: Typically 5-20 through wall thickness
  • Fine Mesh: More subdivisions for better accuracy
  • Coarse Mesh: Fewer subdivisions for faster computation
  • Critical Areas: Use finer mesh near throat and high heat flux zones

Temperature Initialization

  • Ambient Start: 300 K for room temperature startup
  • Preheated: Consider preheating for hot fire simulations
  • Previous Run: Use converged temperatures from prior analysis

Example JSON

{
  "name": "Chamber Wall",
  "category": 5,
  "type": "Solid",
  "materialName": "Copper",
  "wallDelta": 0.003,
  "wallDeltaSubdivisions": 10,
  "wallInitialT": 300.0,
  "chamberCriticalRadius": 0.15,
  "chamberThroatCurvatureRadius": 0.02,
  "coolingChannelLandX": 0.002,
  "branch_gas": "Main Chamber Gas",
  "branch_liquid": "Cooling Channel"
}

Heat Transfer Modeling

Thermal Boundary Conditions

Gas Side (Hot Side)

Heat transfer from hot combustion gases:

  • Convection: Function of gas temperature, velocity, and properties
  • Radiation: High-temperature radiative heat transfer
  • Gas Temperature: Typically 2000-4000 K in main chamber
  • Heat Flux: Can exceed 50 MW/m² in throat region

Liquid Side (Cold Side)

Heat transfer to coolant flow:

  • Convection: Function of coolant properties and flow conditions
  • Nucleate Boiling: Enhanced heat transfer in cooling channels
  • Film Boiling: Degraded heat transfer at very high heat flux
  • Coolant Temperature: Typically 20-200 K for cryogenic propellants

Conduction Through Solid

Governing Equation

Three-dimensional heat conduction:

  • Transient: ∂T/∂t term for time-dependent analysis
  • Steady-State: For equilibrium thermal analysis
  • Material Properties: Temperature-dependent conductivity and specific heat

Numerical Method

  • Finite Difference: Discretization through wall thickness
  • Implicit Scheme: Stable for large time steps
  • Convergence: Iterative solution for nonlinear properties

Cooling System Analysis

Regenerative Cooling

Most common rocket engine cooling method:

Design Parameters

  • Channel Geometry: Rectangular, circular, or custom shapes
  • Channel Spacing: Land-to-channel width ratio
  • Flow Direction: Counter-flow for maximum effectiveness
  • Pressure Drop: Balance cooling effectiveness with pump requirements

Performance Metrics

  • Heat Removal: Total heat extracted by coolant
  • Temperature Rise: Coolant temperature increase
  • Wall Temperature: Maximum metal temperature
  • Margin: Safety factor to material limits

Film Cooling

Supplementary cooling method:

  • Film Injection: Coolant injected along wall surface
  • Coverage: Fraction of surface protected by film
  • Effectiveness: Heat transfer reduction due to film
  • Integration: Combined with regenerative cooling

Material Properties

Thermal Conductivity

Temperature-dependent values:

  • Copper: 400-350 W/m·K (decreasing with temperature)
  • Steel: 45-25 W/m·K (decreasing with temperature)
  • Inconel: 15-25 W/m·K (increasing with temperature)

Specific Heat

  • Copper: 385-480 J/kg·K (increasing with temperature)
  • Steel: 460-600 J/kg·K (increasing with temperature)
  • Inconel: 440-640 J/kg·K (increasing with temperature)

Density

Generally constant with temperature:

  • Copper: 8960 kg/m³
  • Steel: 7850 kg/m³
  • Inconel: 8220 kg/m³

Design Process

Thermal Design Steps

  1. Heat Load Analysis: Determine gas-side heat flux distribution
  2. Cooling Requirements: Calculate required heat removal
  3. Channel Design: Size cooling channels for heat removal and pressure drop
  4. Material Selection: Choose materials for temperature and stress requirements
  5. Mesh Resolution: Select subdivision count for accuracy vs. speed
  6. Validation: Compare results with experimental data or correlations

Critical Considerations

  1. Throat Region: Highest heat flux, most critical thermal design
  2. Material Limits: Avoid exceeding melting point or stress rupture
  3. Thermal Gradients: Large gradients cause thermal stress
  4. Coolant Boiling: Avoid film boiling for effective heat transfer
  5. Transient Effects: Consider startup and shutdown thermal cycling

Common Applications

Main Combustion Chamber

  • Chamber Walls: Cylindrical sections with regenerative cooling
  • Injector Face: High heat flux region requiring effective cooling
  • Material: Typically copper or copper alloy for high conductivity

Nozzle Throat

  • Throat Insert: Highest heat flux location in engine
  • Curvature Effects: Throat radius affects heat transfer
  • Material: Often specialized high-temperature alloys

Nozzle Extension

  • Diverging Section: Decreasing heat flux with expansion
  • Radiation Cooling: May use radiation cooling at low heat flux
  • Material: Can use lighter materials like carbon-carbon

Gas Generator

  • Chamber Walls: Lower heat flux than main chamber
  • Simpler Cooling: May use film cooling or thermal barriers
  • Material: Steel or Inconel for cost and durability

Performance Optimization

Heat Transfer Enhancement

  • Surface Roughness: Increases convective heat transfer
  • Channel Geometry: Optimized shapes for heat transfer and pressure drop
  • Flow Turbulence: Enhanced mixing improves heat transfer
  • Fins/Extensions: Increase surface area on coolant side

Thermal Management

  • Thermal Barriers: Reduce gas-side heat flux
  • Heat Sinks: Absorb transient heat loads
  • Insulation: Reduce external heat loss
  • Preheating: Reduce thermal shock during startup

See Also

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