Computational Fluid Dynamics | CFD Analysis | CFD Basics | Computational Fluid Dynamics Principles And Application | Introduction To Computational Fluid Dynamics

Computational fluid dynamics (CFD) is the science of predicting fluid flow, heat transfer, mass transfer, chemical reactions, and related phenomena by solving the mathematical equations which govern these processes using a numerical process.

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Computational Fluid Dynamics (CFD), sometimes referred to as flow simulation, is a computer simulation technique that allows the fluid flow around or through any product to be analyzed in great detail.

By using this technique, designers can verify that their products will conform to a client’s specifications early in the design cycle, greatly accelerating the product development process.  CFD can be used to calculate design mass-flow rates, pressure drops, heat transfer rates, and fluid dynamic forces such as lift, drag and pitching moments.

The accuracy and fidelity of modern CFD methods has significantly increased the level of design insight available to engineers throughout the design process and therefore greatly reduces companies’ exposure to technical risk when developing thermal and fluid-based products.  The use of CFD in design generally leads to far fewer physical prototypes being necessary during development, far less prototype testing and consequently reduces the time-to-market and cost-to-market substantially.

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Benefits of CFD include:

  • Unmatched insight into systems that may be difficult to prototype or test through experimentation
  • Ability to foresee implications of design changes and optimize accordingly
  • Accurately predict mass flow rates, pressure drops, mixing rates, heat transfer rates & fluid dynamic forces

Applications include:

  • Aerodynamics
  • Industrial Fluid Dynamics
  • Fluid Structure Interaction
  • Heat Transfer
  • Hydrodynamics
  • Multi-phase Flows

Advantages of CFD:

  • Relatively low cost.
  • Using physical experiments and tests to get essential engineering data for design can be expensive.
  • CFD simulations are relatively inexpensive, and costs are likely to decrease as computers become more powerful.
  • Speed.
    • CFD simulations can be executed in a short period of time.
    • Quick turnaround means engineering data can be introduced early in the design process.
  • Ability to simulate real conditions.
    • Many flow and heat transfer processes can not be (easily) tested, e.g. hypersonic flow.
    • CFD provides the ability to theoretically simulate any physical condition.
  • Ability to simulate ideal conditions.
    • CFD allows great control over the physical process, and provides the ability to isolate specific phenomena for study.

    Example: a heat transfer process can be idealized with adiabatic, constant heat flux, or constant temperature boundaries.

    • Comprehensive information.
    • Experiments only permit data to be extracted at a limited number of locations in the system (e.g. pressure and temperature probes, heat flux gauges, LDV, etc.).
    • CFD allows the analyst to examine a large number of locations in the region of interest, and yields a comprehensive set of flow parameters for examination.

    Limitations of CFD:

    • Physical models.
    • CFD solutions rely upon physical models of real world processes (e.g. turbulence, compressibility, chemistry, multiphase flow, etc.).
    • The CFD solutions can only be as accurate as the physical models on which they are based.
  • Numerical errors.
    • Solving equations on a computer invariably introduces numerical errors.
    • Round-off error: due to finite word size available on the computer. Round-off errors will always exist (though they can be small in most cases).
    • Truncation error: due to approximations in the numerical models. Truncation errors will go to zero as the grid is refined. Mesh refinement is one way to deal with truncation error.
  • Boundary conditions.
    • As with physical models, the accuracy of the CFD solution is only as good as the initial/boundary conditions provided to the numerical model.

    Example: flow in a duct with sudden expansion. If flow is supplied to domain by a pipe, you should use a fully-developed profile for velocity rather than assume uniform conditions.

    SolidWorks COSMOS FEA | Power Applications | Electronics Application | Process Application

    Power Application:

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    COSMOS has been widely used in the power industry to study efficiency of sub systems involved in power generation. Combination of what if scenarios can be studied with ease to understand system response and enhance reliability.

    Following Functionalities have been benefited the Power sector immensely:

    • Remaining Life Analysis of Static and Rotating components such as turbine parts
    • Heat transfer analysis of heat exchangers, boilers, pre-heaters, headers among others.
    • Fluid flow analysis in cyclones, waste heat recovery systems, chimneys, cooling towers and environmental and pollution control sub systems
    • Efficiency estimation of pumps
    • Energy flow studies in wind power applications
    • Solutions to Vibration induced failure problems
    • Strength and stiffness calculations for pressure vessels, structural members and tanks
    • Earth quake response (Seismic) Analysis of sub-systems
    • Creep analysis and aging calculations for high temperature applications

    Process Application:

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    COSMOS has found numerous applications in Petrochemical, textile and allied Industries. Renowned process industries world wide have adopted COSMOS to enhance life expectancy, reduce cost and improve reliability and efficiency of sub-systems and component’s.

    Some of the capabilities of COSMOS include:

    • Stress and deflection calculations for pressure vessels, agitators, environment tanks, process equipment’s and comparison to ASME Code
    • Nozzle stress calculations
    • Wind loading, Hydro static pressure testing of process equipment’s and qualification of equipment’s to seismic excitation based on zonal classification.
    • Heat transfer simulation of heat exchangers (Plate type, Shell and Tube Type, Air-Cooled), Super heaters, Evaporators, Condenser’s, Cooling Tanks, Boilers, Distillation Columns and Chillers
    • Fluid induced vibration simulation of columns, tube bundles, pipe supports among others
    • Life expectancy calculation’s for dryers (Static and Rotary), Centrifuges, Rotating equipment’s and load bearing members
    • High Temperature applications involving seals and gaskets
    • Stiffness, Stress and Life calculations for expansion joints

    Electronics Applications:

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    Electronics industry worldwide has adopted COSMOS for quick and accurate simulations to obtain reliable answers for challenging situations arising out of thermal and vibratory input.

    Some of the popular uses include:

    • Shock calculations of enclosures, support structures, electronic systems as per MIL, NAVSEA, BS and Indian Standards for equipment’s used in aircrafts, ships and off road vehicles
    • Thermal management of electronic device enclosures
    • Forced cooling in electronic sub systems and optimization of heat sinks
    • Thermal management of Printed Circuit Boards
    • Vibration analysis for impact printers & Electro-Mechanical actuation systems
    • Natural and Forced convection cooling of controllers ( Internal and External)
    • Heat Transfer efficiency of cold plates.