Pressure surge calculation

We offer professional pressure surge calculations to avoid potential damage in pipework systems. Even with comparatively small pipe lengths and flow rates, pressure surges can have a considerable impact. This makes precise calculations and appropriate safety measures all the more important.

DRAKO fluid dynamics programme - pressure wave calculation in piping systems with general components

DRAKO is a fluid dynamics calculation programme that calculates transient flow processes in complex piping systems. Due to the extensive range of components, the programme opens up almost unlimited application possibilities for flow processes in any flow channels. The programme has a graphical user interface that makes it easy to work with when creating calculation models and evaluating the results.


Range of services

Calculation of

  • Liquids, vapours and gases
  • Two-phase flow
  • Evaporation, condensation
  • Supersonic flow, compression shock
  • Conversion elasticity
  • Fluid-structure coupling

Boundary conditions

  • Open / closed pipe ends
  • Branch and bifurcation
  • Pressure / mass flow / area-time function
  • Heat source as time function
  • Safety valve, bursting disc
  • Non-return flap / valve
  • Valve controlled by own medium
  • Pump, air vessel, ... etc.


As a result, the programme provides time histories of:

  • active components (e.g. valve stroke, pump speed, etc.)
  • Pressure, velocity, mass flow, density at preselected positions
  • Pipe forces, for a later structural-dynamic calculation

Equation of state

The programme can be used to treat any liquids, two-phase mixtures, vapours or gases as fluids. The material model for the corresponding fluid is formed from the following two functions:

  • Density=f(pressure, entropy)
  • Enthalpy=f(pressure, entropy)

A database is available for water, vapour and ideal gas to form these two functions.

Solution method

The following methods are available for solving the differential equation system:

  • the 2nd order difference method according to Mc. Cormack and
  • the method with curved characteristics