Plate Heat Exchanger CFD Simulation: Viscous Heating and Conjugated Heat Transfer

A comprehensive computational fluid dynamics analysis of a novel plate heat exchanger design incorporating parallel solid plates with corner-mounted flow channels. This simulation captures the complex interplay between convective and conductive heat transfer mechanisms, demonstrating the unique thermal characteristics of this unconventional heat exchanger configuration.

Heat Exchanger Configuration and Design Approach

This simulation investigates a specialized plate heat exchanger design featuring four solid plates with integrated corner pipes, creating a unique thermal pathway that differs from conventional plate heat exchanger configurations. The study demonstrates how this arrangement facilitates heat transfer through a combination of convection in the fluid channels and conduction through the solid plates.

Geometric Specifications

• Plate Dimensions: 2m × 2m with 0.2m thickness
• Flow Channels: Four corner-mounted pipes with 0.2m diameter and 1.1m length
• Material Configuration: Single-part solid construction with integrated flow passages
• Flow Arrangement: Counter-flow configuration with opposing inlet locations

Computational Domain

• Mesh Structure: Unstructured grid with 2,216,379 elements
• Domain Components: Solid plates, fluid channels, fluid-solid interfaces
• Discretization Quality: Refined mesh near fluid-solid boundaries for accurate CHT modeling

Simulation Methodology and Physical Models

Conjugated Heat Transfer Approach

• Heat Transfer Mechanisms: Simultaneous modeling of:
  • Convection between fluid and pipe walls
  • Conduction through solid plates
  • Thermal interface coupling between domains
• Solution Strategy: Pressure-based solver for incompressible flow
• Analysis Type: Steady-state simulation with coupled energy equation

Operating Conditions

• Working Fluid: Water with temperature-dependent properties
• Flow Parameters: Equal velocity in all channels
• Temperature Differential: 20°C and 40°C inlet temperatures in counter-flow arrangement
• Boundary Conditions: Specified velocity inlets and pressure outlets
• Simplifications: Negligible gravitational effects

Modeling Considerations

• Viscous Heating: Inclusion of energy dissipation due to fluid friction
• Turbulence Model: Appropriate model for pipe flow conditions
• Material Properties: Temperature-dependent thermal properties for water
• Interface Treatment: Continuous temperature and heat flux at fluid-solid boundaries

Results and Performance Analysis

Thermal Characteristics

• Temperature Distribution: Visualization of thermal gradients across solid plates
• Heat Transfer Pathways: Identification of primary conduction paths between channels
• Thermal Spreading: Analysis of heat diffusion through solid medium
• Temperature Profiles: Examination of fluid temperature evolution along flow paths

Flow Behavior

• Pressure Distribution: Characterization of pressure gradients in flow channels
• Velocity Patterns: Analysis of flow development in pipe sections
• Turbulence Characteristics: Evaluation of turbulent kinetic energy distribution
• Viscous Effects: Assessment of viscous heating contribution to thermal performance

Performance Metrics

• Heat Transfer Effectiveness: Evaluation of overall thermal efficiency
• Temperature Approach: Analysis of terminal temperature differences
• Pressure Drop: Quantification of hydraulic resistance
• Flow Distribution: Assessment of flow uniformity across channels

Engineering Insights

• Design Implications: Guidance for optimizing plate thickness and channel placement
• Performance Enhancement: Strategies for improving thermal effectiveness
• Material Selection: Impact of solid thermal conductivity on overall performance
• Operational Considerations: Effects of flow rate on heat transfer characteristics

This detailed simulation provides valuable insights into the thermal-hydraulic behavior of this unconventional plate heat exchanger design. The results demonstrate how the combination of strategic channel placement and solid conduction pathways can create effective heat transfer between fluid streams, offering design guidance for specialized heat transfer applications where traditional plate heat exchanger configurations may not be suitable.