Can Flownex model the transient depressurization of a sealed high-pressure tank after a valve is opened to atmosphere? For example, can a tank be initialized at a high pressure, connected to a valve and downstream piping with an atmospheric boundary condition, and then simulated to observe the pressure decay over time?
In addition, can Flownex model a vacuum generation process where a tank initially at atmospheric pressure is evacuated using a pump, allowing users to determine the achievable vacuum level and the time required to reach it?
Yes, Flownex can model both tank depressurization (blowdown) and vacuum generation processes using transient simulations.
For tank depressurization studies, a tank can be initialized at a specified pressure and connected to a downstream flow path containing components such as valves, pipes, and pressure boundaries. During a transient simulation, actions can be used to open the valve, allowing the fluid to discharge from the tank. Flownex will then calculate the resulting transient behavior, including the changing tank pressure, temperature, mass inventory, and flow rates as the tank depressurizes over time.
Similarly, Flownex can be used to model vacuum generation by connecting a tank to a vacuum pump and performing a transient analysis. The simulation can track the pressure reduction inside the tank and predict how quickly the system approaches the pump's attainable vacuum level. The final pressure achieved will depend on factors such as the pump characteristics, system leakage, flow restrictions, and operating conditions.
Several published studies and validation examples demonstrate the use of Flownex for blowdown and pressure-transient analyses. These references include investigations of transient pipe-network flows, propellant tank pressurization systems, and verification and validation studies that include tank pressure evolution during transient events.