Characteristic problems in the industry from the point of view of thermal-hydraulics are related to water hammer investigation in the pipeline systems, sizing of safety valves and assessment of heat transfer coefficients of components and processes. Water hammer can be of multiple nature and the most typical one is when waterfront hits, e.g. a closing valve. At certain conditions resulting pressure can exceed construction pressure which in turn can lead to damage of the pipeline. The incident can be roughly estimated by analytical methods. For more complex systems and arrangement numerical methods are employed. When it comes to safety valves we perform calculation of backpressure in closed discharge systems. According to EN ISO 4126:Part 1 pressure in the system should be maintained below 10% of the safety valve pressure. Our analyses review back pressure in manifold discharge systems and come with recommended actions to maintain safe operation. Heat transfer coefficient is another relevant parameter that our clients ask for. The coefficient is used, e.g. for stress analysis calculation of components under cooling or warming.

Calculation methods

In our calculations we use among other things Computational Fluid Dynamics (CFD). CFD is a calculation method that makes it possible to simulate complex fluid phenomena with no need for experiments. The CFD study can be combined with analysis of Flow-Induced Vibration (FIV) or Fluid Structure Interaction (FSI) to give a necessary basis for assessing component life-time or design optimization to name a few. We offer support and analyses for customers using the most popular CFD solvers on the market, as ANSYS and open-source OpenFOAM. Different models and approaches can be validated, verified and optimized. Usually simulations performed with simple two-equation models, as Standard k-ε, Realizable k-ε, Standard k-ω, SST k-ω, as well as Realizable Stress Model, give an understanding for the most of the technical problems. 

More complex calculations with focus on eddies and swirls behind an object, e.g. a case of thermocouple in the pipe, can be performed with Large Eddie Simulation model, depending on model complexity and Reynolds number. CFD & FIV analyses can give answers to most of the common technical and industry problems related to transport phenomena, heat transfer, acoustics and vibrations. CFD methods can be employed in calculations of flammable vapors in rooms (ATEX problem), mixing at T-junction or assessing the size and position of steam plume from cooling towers.

Typical analyses

  • Water hammer calculations
  • Sizing of safety valves
  • Assessment of heat transfer coefficient
  • CFD Calculations of check valves
  • CFD Steam plume & wind rose
  • CFD Micro-climate properties and ventilation in office buildings
  • CFD Concentration of explosive vapors in a compartment
  • CFD Flow-Induced Vibration (FIV)
  • CFD Large Eddy Simulation (LES)