Every electronic device generates heat. If a large number of devices work on limited space, overheating might occur. As detectors can produce inaccurate data, CFD (Computational Fluid Dynamics) thermal simulation might be used to prevent overheating. We can also use CFD method to simulate the flow of gas inside TOF-MPD (Time of Flight – Multi Purpose Detector) so we can choose the best variant of gas distribution system. CFD is a powerful numerical method which can be used to analyse the flow of fluid or heat transfer.