Objectives  The bench test is an important means for the design and verification of steam systems, and the accuracy of the boundary condition is a critical factor for studying the characteristics of the bench test.

  Methods  In order to propose a feasible dynamic flow boundary control method, based on the change requirements of steam inlet flow in the bench test of a steam system, the two schemes of PID closed-loop control and open-loop control are proposed, and simulation comparison and analysis are carried out. In the GSE simulation system, JTopmeret modules are employed to establish the whole steam test system, the optimization of the modules and correction of parameters are processed on the basis of the data detected in the steam test, and the simulation data is compared with the experimental data to verify the accuracy and validity of the simulation model.

  Results  For the control requirements of reducing steam flow linearly by 20 t/h within 10 s, the simulation results show that the open-loop control scheme allows the control of boundary conditions to be achieved after several iterations, while using the traditional PID closed-loop control scheme makes it difficult to control the boundary as required. The test results show that the flow change at the steam inlet meets the test requirements of the bench test, and is consistent with the simulation results.

  Conclusions  The results of this research can provide references for the boundary control of steam system bench tests.