The PULSIM project – short for pulsation simulator – was initiated as a Joint Industry Project at the Institute of Applied Physics “TPD” of TNO in Delft, The Netherlands, in 1968. The sponsors were Dutch industries, which, as users and manufacturers of compressor systems, felt the necessity of an improved method of vibration abatement. By the end of 1969, the first calculations could be performed.

After construction of the PULSIM analog computer and a try-out period TNO started to carry out pulsation studies on a regular basis and the need for sponsoring disappeared. Therefore in 1972 the formal relation between PULSIM and sponsors was terminated and facilities have been made available to others on a commercial basis since.

TNO improved the analog, validated it with field measurements, and over the years we have continuously been carrying out further research into the physics of fluid dynamics. The Fluid Dynamics (“PULSIM”) group of TNO has thus become – and still is – world-leading on subjects like pulsations/vibrations in pipe systems of reciprocating machines, flow-induced pulsations (e.g. “singing” risers), flow-induced vibrations, pulsations and stability of centrifugal machines, and multi-phase flow.

In 1982 the first digital computer program version of PULSIM was built. Since then, the computer program has been continuously improved. New models were developed and validated in contract research or joint industry projects, and some of these found their way to the engineering consultancy business that PULSIM had also become. We developed and promoted the Mechanical Response Analysis, calculating vibrations and cyclic stresses due to pulsation-induced forces.

The calculation of mechanical responses of the piping structure due to pulsations started in 1976, initiated because of a vibration problem in gas compressor station Spijk, The Netherlands. Several finite-element mechanical simulation programs have been used over the years (for example also the TNO program DIANA), and in 1993 the commercial package ANSYS proved to be the most efficient platform to build the further PULSIM mechanical functionalities on.

To stay ahead of competition, the TNO consultants who carried out pulsation studies demanded ever more user-friendly and more efficient PULSIM software. This resulted in a 3D modeler for pipe systems (P3D, 1999). The graphical representation of the model on the screen reduced the risk of errors, and made it possible to create more complex system models. We soon after combined this 3D PULSIM with an exporter to ANSYS, for an efficient and robust generation of ANSYS models to carry out the mechanical response calculations.

In 2010 the first version of “PulsimSuite” was launched. This 3D modeler could also represent the mechanics  of supporting structures, coolers, etc., so that the interfacing with ANSYS was even more straightforward. With PulsimSuite, TNO also started to offer the full PULSIM functionalities as a commercial software tool, after having built up some commercialization experience with “limited functionality” programs like DamperSim Jr. (2000) and DamperSim (2004).

PULSIM, the pulsation simulation analog computer