Solver iconSolver Approach

The analysis and design of thermal-fluid networks in Flownex are based on the numerical solution of the governing equations of fluid dynamics for compressible gas, incompressible liquids, homogeneous two phase fluids and heat transfer through solid structures.

Flownex solves conservation of mass, momentum and energy to obtain the mass flow, pressure and temperature distributions of fluids and solids throughout the complete network. This fundamental approach enables Flownex to predict complex phenomena such as pressure and temperature waves in pipes and buoyancy effects in due to variation of elevation in systems. 

An important feature of the fundamental network approach is that elements such as pipes, heat exchangers and the reactor, although depicted on the systems level as single elements or pairs of elements, can be discredited into either sub-networks or multidimensional regions. The discredited and multi-dimensional components allow users to take full account of the thermal inertia of the system. 

The fundamental approach is used for simulation, design and optimization of thermal-fluid networks.

 

Fundamental Approach for Thermal-Fluid Network Simulation

The objective of any thermal-fluid network analysis is to determine flow rates, pressures, temperatures and/or heat transfer rates for components in the network. Every component in a thermal-fluid network has to comply with the system specification and the individual components must function correctly as part of the integrated system. When designing thermal-fluid networks it is essential to accurately predict the flow rates through the components, as well as the temperature distributions and heat transfer rates throughout the network. Flownex can be used to assess the performance and operating conditions of components in complex unstructured thermal-fluid networks.

The analysis of thermal systems is often complicated by various factors, for example, the complex nature of fluid flow and heat transfer processes. Some of the characteristics commonly encountered in thermal systems that complicate their analysis are listed below.

  • Time-dependent flow.
  • Multidimensional flow.
  • Complex geometries.
  • Complicated boundary conditions.
  • Coupled transport phenomena.
  • Turbulent flow.
  • Structural- and phase- change.
  • Energy losses and irreversibility.
  • Variety of energy sources.

 

By using the fundamental modeling approach adopted by Flownex users can take into account most commonly encountered in thermal systems that complicate their analysis.

 

 

Special Capabilities & Advantages of the Fundamental Approach

By taking conservation of mass, momentum and energy for flow and the conservation of energy for solid structures into account Flownex allows you to simulate:

  • Dynamic simulation and prediction of system behavior.
  • The dynamic variation and calculation of flow velocity, pressure, temperature, heat transfer rates, shaft dynamics of turbo machinery and system control.
  • Simulation of plant scenarios plant startup, shut down, accidents and maintenance procedures.
  • Branching of flow through junctions allowing for optimization of flow branching ensuring even flow distribution through multiple junctions.
  • System Inertia.
  • Buoyancy driven flows, taking into account elevation.
  • Natural Convection.
  • Rotational momentum for rotating pipes ensuring accurate of prediction of flow through cooling flow channels in rotating turbine blades.