An adventitious flow field has a great impact on the operational reliability of pumps; therefore, it is important to study pump flow characteristics to reduce the noise, vibration, and cavitation performance of pumps. To study the pressure fluctuation characteristics of the hose pump, a three-dimensional two-way fluid structure coupling model of the hose pump was established. The transient structural module, fluid flow (fluent) module, and system coupling module of ANSYS Workbench 19.0 were used to simulate the unsteady multiple working conditions of the hose pump. The accuracy and reliability of the calculation results from the fluid solid coupling simulation were verified via experimentation. The results show that the roller pass frequency is the main frequency of the pressure fluctuation at the outlet of the hose pump. When the plane of the deformation recovery area is small, the pressure pulsation amplitude is large, and the outlet pressure and speed are large. Due to the irregular backflow of the fluid, stall zones of different sizes form, the outlet pressure is closer to a sinusoid when there is no pressure. The higher the rotating speed is, the faster the pressure roller leaving the hose, the higher the pressure pulsation, and the larger the stall zone. Therefore, the best way to reduce the pressure pulsation in the pump is to optimize the geometry of the pressure roller and change the outlet angle of the hose.

The three-blade combined agitator consists of two propulsion blades of the same type (including planar propeller blades b, δ = 36.87°) and a curved blade (θ = 30°). Using numerical simulation methods, the power characteristics, flow field distribution, turbulence characteristics and dead zone percentage of two kinds of three-blade combined agitators (TBCAs) from laminar flow to turbulent flow in a mixing vessel were studied. Moreover, the torque measurement method was used to perform experimental verification. The results show that the predicted power curve is consistent with the experimental results. The fluid velocity near the propeller blades in the TBC-B type agitator (δ = 36.87°) is significantly high, and the maximum increase of the total velocity can reach 30.3%. The fluid flow velocity near the curved blades is increased, and the radial diffusion ability of the fluid at the bottom of the stirring vessel is enhanced. When mixing low-viscosity fluids, the TBC-B type agitator can increase the fluid velocity near the paddle area, with a maximum increase of 22.1%. The vertical combination of curved blades and planar propeller blades can effectively reduce the tangential velocity and increase the axial and radial velocities. When stirring high-viscosity fluids, the speed of the TBC-B type agitator in the near paddle area and far end of the blade is higher than that of the TBC-A type agitator. Under the same conditions, the TBC-B-type agitator exhibits superior fluid discharge performance and can be used in a wider range of viscosities. When Re = 44,910, the dead zone percentage of the TBC-A type agitator is 0.0216. The percentage of dead zones produced by the TBC-B-type agitator is smaller, and the mixing effect is superior to that of the TBC-A-type agitator.

This work presents a robust non-deterministic free vibration analysis for engineering structures with random field parameters in the frame of stochastic finite element method. For this, considering the randomness and spatial correlation of structural physical parameters, a parameter setting model based on random field theory is proposed to represent the random uncertainty of parameters, and the stochastic dynamic characteristics of different structural systems are then analyzed by incorporating the presented parameter setting model with finite element method. First, Gauss random field theory is used to describe the uncertainty of structural material parameters, the random parameters are then characterized as the standard deviation and correlation length of the random field, and the random field parameters are then discretized with the Karhunen–Loeve expansion method. Moreover, based on the discretized random parameters and finite element method, structural dynamic characteristics analysis is addressed, and the probability distribution density function of the random natural frequency is estimated based on multi-dimensional kernel density estimation method. Finally, the random field parameters of the structures are quantified by using the maximum likelihood estimation method to verify the effectiveness of the proposed method and the applicability of the constructed model. The results indicate that (1) for the perspective of maximum likelihood estimation, the parameter setting at the maximum value point is highly similar to the input parameters; (2) the random field considering more parameters reflects a more realistic structure.

The distribution of heating gun ends plays a decisive role in the sidewall properties of finished rotomolded products. To obtain the optimal distribution of the end face of a rotational molding heating gun, the temperature response of the end-face mold under heating gun heating was investigated, and an analysis method based on numerical simulation is proposed. The FDS (fire dynamics simulator) was used to construct a heating model of the heating gun, simulate and obtain a heatmap of the temperature field distribution of a heating gun of Φ30–70 mm, and determine the optimal diameter and heating distance of the heating gun. ANSYS was used to establish the thermal response model of the heat-affected mold, which was combined with the mold structure and thermophysical properties of steel. A temperature field distribution on the inner wall surface of Φ30, Φ50, and Φ70 mm heating guns when heating at each diameter of the end face was obtained and the distribution position of the end face of each diameter heating gun was determined. ANSYS was used to establish the thermal response model of the end-face mold and obtain the temperature field distribution of the inner wall surface of the end-face mold. The size of the heat-affected area of each diameter heating gun was combined, the end-face heating gun distribution was optimized, and the optimal heating gun end-face distribution was obtained. An experimental platform was built, and a validation experiment was set up. Through the analysis and processing of the data of three experiments, the temperature variation curve of each diameter on the inner surface of the end-face mold was obtained. We compare and analyze the simulation and experimental results to determine the feasibility of the FDS + ANSYS method and the correctness and accuracy of the simulation model and the results.

Hypersonic magnetohydrodynamic (MHD) control has considerable potential for optimizing the aerodynamic and thermal characteristics of hypersonic vehicles and managing flows such as boundary layer transitions. As key factors influencing MHD control, magnetic field parameters are a central focus of research. To address the challenges in simulating 3D magnetic fields and assessing their impact on MHD control, this study employed a 3D, low-magnetic-Reynolds-number MHD model to conduct numerical simulations. These simulations helped investigate hypersonic MHD control under various magnetic field types and configurations and analyze the underlying mechanisms and their effects on the flow field and thermal/force distributions. The results indicate that the direction of the Lorentz force is jointly determined by the orientations of the magnetic field and the flow field. Different Lorentz force directions influence the shock stand-off distance through distinct mechanisms, near-wall Lorentz forces can effectively regulate the increase or decrease in surface heat flux. Under the computational conditions of this study, considering both MHD thermal protection performance and the MHD shock control effectiveness, the optimal magnetic control parameters for the two-dimensional solenoid model are determined as LM = 0.26 m and x0 = 0.04 m. Through three-dimensional magnetic field analysis, the optimal magnetic configuration for the three-dimensional model is identified as M9. The external flow fields generated by spatial magnetic configurations M4, M5, M7, and M8 exhibit significant asymmetry, and the numerical simulation results provide theoretical support for the application of magnetic field in hypersonic vehicle attitude control.