There was a download of VacTran 3.47.3 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. VacTran belongs to Photo & Graphics Tools. The most popular version of the program 3.4. The default filename for the program's installer is VacTran.exe. This program is a product of Professional Engineering Computations (PEC).
From the developer:
VacTran was designed to facilitate the process of modeling a vacuum system. It was developed to solve common, real problems faced by industry and national labs. Rapid and accurate modeling of vacuum systems enables informed decisions and success in new product development and advanced experiments.
You may want to check out more software, such as Javelin5, which might be similar to VacTran.