Steam–water injectors have been widely applied in various industrial fields because of their compact and passive features. Despite its straightforward mechanical design, the internal two-phase condensing flow phenomena are extremely complicated. In present study, a numerical model has been developed to simulate steam–water interfacial characteristics in the injectors based on Eulerian–Eulerian multiphase model in ANSYS CFX software. A particle model is available for the interphase transfer between steam and water, in which a thermal phase change model was inserted into the model as a CFX Expression Language (CEL) to calculate interphase heat and mass transfer. The developed model is validated against a test case under a typical operating condition. The numerical results are consistent with experimental data both in terms of axial pressure and temperature profiles, which preliminarily demonstrates the feasibility and accuracy of particle model on simulation of gas–liquid interfacial characteristics in the mixing chamber of injector. Based on the dynamic equilibrium of steam supply and its condensation, interfacial characteristics including the variation of steam plume penetration length and steam–water interface have been discussed under different operating conditions. The numerical results show that steam plume expands with steam inlet mass flow rate and water inlet temperature increasing, while it contracts with the increase of water inlet mass flow rate and backpressure. Besides this, the condensation shock position moves upstream with the backpressure increasing.

In the published experimental results, it has been observed that when high-speed steam spurt into the subcooled waterflow, the total pressure along the axial direction at trailing edge of the steam plume shows a pressure-lift. To reveal the mechanism behind this phenomenon, this study utilizes a particle model to investigate the pressure profile of steam jet condensation in subcooled water flow in a narrow pipe. A numerical model based on the Eulerian–Eulerian multiphase model has been developed to accurately simulate the characteristics of pressure profile along the axial direction. The model’s validity is established by comparing the steam plume shape and temperature profiles with the experimental data. By analyzing the total pressure profile of the axis and the contours of gas volume fraction, it is found that there exists a pressure-lift phenomenon at trailing edge of the steam plume. The dynamic pressure of the water also shows a pressure-lift at this position, so it can be inferred that the dynamic pressure of the water is the main factor of the total pressure-lift.

In order to solve the problem of reliability analysis in which the thermal warping deformation of the automobile brake disc presents an implicit complex nonlinear relationship with the design variables, a reliability analysis method of thermal warping deformation of brake disc based on AK-MCS method was proposed by combining Kriging model, active learning strategy and Monte Carlo Simulation. The Kriging model was used to construct the surrogate model of the thermal warping deformation performance function of the brake disc, and the continuous updating of the Kriging model was realized by establishing the learning function U. Based on this, Monte Carlo Simulation method was used to calculate the reliability of the thermal warping deformation of the brake disc, and the failure probability is 0.0035. The prediction accuracy of the Kriging model was tested and the results show that it meets the engineering requirements, so the reliability analysis results were proved to be efficient. The proposed method can be used for reference for the reliability analysis of automobile key parts.

A three-dimensional numerical model of a water-driven steam ejector was developed using the Euler-Euler two-fluid framework. A direct-contact condensation (DCC) heat and mass transfer model was employed to simulate the complex two-phase flow and energy exchange. The distributions of gas-liquid phases, pressure, and temperature were obtained to evaluate performance. Results indicate that within the investigated operating range (p_p = 140–160 kPa), the entrainment ratio (ER) and temperature rise (DT) are highly coupled, with DT varying from 5.33 to 11.49 K. The maximum temperature rise of 11.49 K was achieved at p_p = 140 kPa, T_p = 310 K, p_s = 100 kPa, and p_b = 92 kPa. It was found that a distinct pressure jump occurs at the throat, where the entrained steam is completely condensed, followed by rapid pressure recovery in the diffuser. The steam plume length and condensation zone are strongly governed by back pressure (p_b); Increasing p_b from 92 to 114 kPa leads to a continuous reduction in ER and shifts the peak condensation zone upstream. Furthermore, the study reveals that elevated back pressure suppresses steam entrainment and shortens the condensation length, eventually leading to flow reversal when a critical p_b is exceeded. This work provides detailed physical insight into DCC mechanisms and offers quantitative references for the design of ejector-assisted components in advanced energy systems.