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To investigate the tank deformation behavior under ultra-low temperature and high-flow-rate filling conditions, a thermal-fluid-structure coupling numerical model for liquid hydrogen (LH 2 ) filling into the storage tank was established. The temperature variation and corresponding structural deformation of the tank during the ultra-low temperature high-flow-rate LH 2 filling process were systematically analyzed. The research findings reveal that at a filling flow rate of 8 m 3 /min and a pressure difference of 0 MPa, 84.1% of the tank volume was filled with fuel within 960 s, resulting in a deformation of 30.418 mm. When the outlet pressure difference increased from 0 to 0.1 MPa, the fuel filling ratio reached 78.5% in 500 s, with a corresponding deformation of 28.907 mm. As the outlet pressure difference further increased from 0.1 to 0.2 MPa, the filling ratio decreased to 45% with a filling duration of 576 s, and the deformation was reduced to 24.527 mm. When the filling flow rate was increased to 15 m 3 /min, 44% of the tank volume was filled in 250 s, with a deformation of 27.043 mm. Comparative analysis demonstrates that high-flow-rate LH 2 filling achieves significantly higher efficiency than low-flow-rate filling, while the structural deformation induced by high-flow-rate filling is larger than that by low-flow-rate filling. When pre-cooling measures were adopted, the tank deformation after switching to high-flow-rate filling was notably smaller than that without pre-cooling. It is therefore concluded that pre-cooling measures are essential for ultra-low temperature high-flow-rate LH 2 filling, as they can significantly improve the LH₂ filling efficiency while effectively reducing the thermal deformation of the tank structure.

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

A complex operating environment poses significant challenges to the design of ramjet combustion chambers as high-enthalpy wind tunnels and their associated high-temperature, high-pressure combustion chambers continue to advance. This study developed a thermal–fluid–structure coupling finite element (FE) model based on the computational fluid dynamics (CFD) numerical simulation method to simulate the service conditions of combustion chambers under varying structures. Subsequently, FE simulation results were used to study the influences of combustion chamber structure on fluid flow characteristics, variation in cooling water pressure, temperature and stress of a combustion chamber wall. The results showed that after cooling water entered the chamber as a stable jet, it impacted the wall surface and formed a bidirectional vortex flow, which then entered the cooling water channels. Modifying the slope of a cooling water channel can effectively reduce pressure within the combustion chamber. It is noteworthy that the inlet equivalent stress of a combustion chamber decreases with an increasing slope, whereas outlet equivalent stress increases correspondingly. Finally, through comprehensive analysis, the optimal slope of a cooling water channel was determined to be 0.3°. This work provides essential theoretical insights for optimizing the design of combustion chambers.

The deflection magnet (DM) is the most important component of the Neutral Beam Injection (NBI) system of Experimental Advanced Superconducting Tokamak (EAST), which can magnetically deflect the un-neutralized charged particles after the neutralized process of the beam is extracted from the ion source, and then form a neutral beam injected into the tokamak. Under the operating conditions of the NBI system, by using the thermocouple monitoring system in the experiment, it can be found that the currently operating DM beam collimator has a quite high temperature rise. It is necessary to redesign the DM beam collimator to improve its heat transfer performance. The parallel arrangement of multiple rows of tubes is proposed as the basic method for the redesign of the beam collimator of DM, the thermal-fluid-structure analysis model of this redesign model is established and its temperature field, pressure field and stress field are analyzed. Taking the surface temperature of the beam collimator, the overall dimension after the total tube combination and the pressure drop of the whole structure of collimator as the optimization objectives, and setting the fluid velocity, the tube’s inner diameter and the number of tube rows as the design variables, the optimized design scheme of the beam collimator structure is obtained. From the results of simulation, the new structure can better meet the operation requirements of DM, and its maximum temperature rise is well controlled, which is expected to meet the long pulse operation requirements of the NBI system. The proposed simulation and design optimization method can provide a certain reference for the design and optimization of other high-heat-flux structures in complex large-scale neutral beam systems in the future.

The application of multi-branch pinnate drilling has great prospects in gas control. Although there are many studies on the parameters of multi-branch plume drilling, the mathematical model used in the study is still not sufficient for the addition of the slippage effect and thermodynamic changes. In this paper, a thermal–fluid–solid coupling model is used to study the influence of branch angle and branch length on the extraction effect in high-gas and extra-thick coal seams. The reliability of the model is verified by simulating an onsite extraction environment to fit the onsite gas production rate. Under identical simulation conditions, the experiment investigated the gas extraction performance of boreholes with varying branch angles (30°, 40°, 50°, and 60°) and branch lengths (50 m, 75 m, 100 m, and 125 m). The results show that temperature affects the dynamic viscosity of gas, which in turn affects the flow rate. The slippage effect affects permeability. When the branch angle is less than 50°, the increase in the branch angle can expand the control range of drilling. By continuing to increase the angle, the improvement in the extraction effect is weakened. As the branch angle exceeds 50° and continues to increase, the branch borehole progressively approaches the edge of the coal seam. At this time, the overall control range of the borehole is greatly increased, and the gas extraction effect is improved. The increase in the branch length leads to a considerable improvement in the extraction effect. When the branch length is below 100 m, the improvement in extraction efficiency diminishes progressively with increasing branch length. This is because the effect of increasing the branch length on improving the overall control range of the borehole is weakened. When the branch length exceeds 100 m and continues to increase, the branch borehole approaches the edge of the coal seam. The overall control effect of drilling has been greatly improved. The extraction effect of boreholes has increased significantly compared with before.

Purpose High pressure and high speed of the axial piston pump can improve its power density, but they also deteriorate the thermal-fluid-structure coupling effect of the friction pairs. This paper aims to reveal the coupling mechanism of the pump, for example, valve plate pair, by carrying out research on multi-physics field coupling. Design/methodology/approach Considering the influences of temperature on material properties and thermal fluid on structure, the thermal-fluid elastic mechanics model is established. A complete set of fast and effective thermal-fluid-structure coupling method is presented, by which the numerical analysis is conducted for the valve plate pair. Findings According to calculations, it is revealed that the temperature and pressure evolution laws of oil film with time, the pressure distribution law of the fluid, stress and displacement distribution laws of the solid in the valve plate pair. In addition, the forming history of the wedge-shaped oil film and mating clearance change law with rotational speed and outlet pressure in the valve plate pair are presented. Originality/value For an axial piston pump operating under high speed, high pressure and wide temperature range, the multi-physics field coupling analysis is an indispensable means and method. This paper provides theoretical evidence for the development of the pump and lays a solid foundation for the research of the same kind of problem.

This article presents a fluid–elastic structure interaction (FSI) problem when the temperature variation of the two media is also taken into account. We introduced the mathematical description of this interaction in a recent article. Our model includes the coupling between the fluid and the elastic medium equations and, in addition, the coupling with the temperature equations. The novelty of this approach is that we succeed in analyzing a complicated double-coupled problem that allows us to describe more complex physical phenomena both from the theoretical and numerical points of view. Since the main goal of this article is to analyze the influence of an exterior field of temperature on fluid pressure variations, the theoretical results obtained in our previous article are completed with qualitative properties concerning the fluid pressure, such as existence, regularity and uniqueness. Our study continues with approximation schemes: in order to improve the unknowns regularity, we introduce the pressure approximation by a sequence of viscoelastic pressure functions and we prove the weak convergence of this sequence to the pressure; then, we present a numerical approximation scheme with stability and convergence results and Uzawa’s algorithm. The last part of the article is devoted to numerical simulations that rely on the numerical schemes introduced and studied before and highlight some physical phenomena related to the considered problem.

Purpose – The aim of this study is to investigate the effects of offset angle in wave soldering by using thermal fluid structure interaction modeling with experimental validation. Design/methodology/approach – The authors used a thermal coupling approach that adopted mesh-based parallel code coupling interface between finite volume-and finite element-based software (ABAQUS). A 3D single pin-through-hole (PTH) connector with five offset angles (0 to 20°) on a printed circuit board (PCB) was built and meshed by using computational fluid dynamics preprocessing software called GAMBIT. An implicit volume of fluid technique with a second-order upwind scheme was also applied to track the flow front of solder material (Sn63Pb37) when passing through the solder pot during wave soldering. The structural solver and ABAQUS analyzed the temperature distribution, displacement and von Mises stress of the PTH connector. The predicted results were validated by the experimental solder profile. Findings – The simulation revealed that the PTH offset angle had a significant effect on the filling of molten solder through the PCB. The 0° angle yielded the best filling profile, filling time, lowest displacement and thermal stress. The simulation result was similar to the experimental result. Practical implications – This study provides a better understanding of the process control in wave soldering for PCB assembly. Originality/value – This study provides fundamental guidelines and references for the thermal coupling method to address reliability issues during wave soldering. It also enhances understanding of capillary flow and PTH joint issues to achieve high reliability in PCB assembly industries.

Hybrid corrugated sandwich (HCS) plates have become a promising candidate for novel thermal protection systems (TPS) due to their multi-functionality of load bearing and thermal protection. For hypersonic vehicles, the novel TPS that performs some structural functions is a potential method of saving weight, which is significant in reducing expensive design/manufacture cost. Considering the novel TPS exposed to severe thermal and aerodynamic environments, the mechanical stability of the HCS plates under fluid-structure-thermal coupling is crucial for preliminary design of the TPS. In this paper, an innovative layerwise finite element model of the HCS plates is presented, and coupled fluid-structure-thermal analysis is performed with a parameter study. The proposed method is validated to be accurate and efficient against commercial software simulation. Results have shown that the mechanical instability of the HCS plates can be induced by fluid-structure coupling and further accelerated by thermal effect. The influences of geometric parameters on thermal buckling and dynamic stability present opposite tendencies, indicating a tradeoff is required for the TPS design. The present analytical model and numerical results provide design guidance in the practical application of the novel TPS.