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This study aims to investigate the influence mechanism of thermal-mechanical deformations on the CO₂ mixture gases dry gas seal (DGS) flow field and compare the deformation characteristics and sealing performance between two-way and one-way thermal-fluid-solid coupling models.

The authors established a two-way thermal-fluid-solid coupling model by using gas film thickness as the transfer parameter between the fluid and solid domain, and the model was solved using the finite difference method and finite element method. The thermal-mechanical deformations of the sealing rings, the influence of face deformation on the flow field and sealing performance were obtained.

Thermal-mechanical deformations cause a convergent gap between the two sealing end faces, resulting in an increase in the gas film thickness, but a decrease in the gas film temperature and sealing ring temperature. The axial relative deformations of rotating and stationary ring end faces caused by mechanical and thermal loads in the two-way coupling model are less than those in the one-way coupling (OWC) model, and the gas film thickness and leakage rate are larger than those in the OWC model, whereas the gas film stiffness is the opposite.

This paper provides a theoretical support and reference for the operational stability and structural optimization design of CO₂ mixture gases DGS under high-pressure and high-speed operation conditions.

Two disastrous Tsunamis, one on the west coast of Sumatra Island, Indonesia, in 2004 and another in North East Japan in 2011, had seriously destroyed a large number of bridges. Thus, experimental tests in a wave flume and a fluid structure interaction (FSI) analysis were constructed to gain insight into tsunami bore force on coastal bridges.

Various wave heights and shallow water were used in the experiments and computational process. A 1:40 scaled concrete bridge model was placed in mild beach profile similar to a 24 × 1.5 × 2 m wave flume for the experimental investigation. An Arbitrary Lagrange Euler formulation for the propagation of tsunami solitary and bore waves by an FSI package of LS-DYNA on high-performance computing system was used to evaluate the experimental results.

The excellent agreement between experiments and computational simulation is shown in results. The results showed that the fully coupled FSI models could capture the tsunami wave force accurately for all ranges of wave heights and shallow depths. The effects of the overturning moment, horizontal, uplift and impact forces on a pier and deck of the bridge were evaluated in this research.

Photos and videos captured during the Indian Ocean tsunami in 2004 and the 2011 Japan tsunami showed solitary tsunami waves breaking offshore, along with an extremely turbulent tsunami-induced bore propagating toward shore with significantly higher velocity. Consequently, the outcomes of this current experimental and numerical study are highly relevant to the evaluation of tsunami bore forces on the coastal, over sea or river bridges. These experiments assessed tsunami wave forces on deck pier showing the complete response of the coastal bridge over water.

This paper aims to acquire the phase distribution and sealing performance of supercritical carbon dioxide (SCO₂) dry gas seals with phase transitions.

The SCO₂ spiral groove dry gas seal is taken as the research object. The finite differential method is applied to solve the governing equations. Furthermore, the phase distribution and the sealing performance are obtained. Compared to the ideal gas model, the effect of phase transitions on sealing performance is also explored.

Vaporization is likely to occur near the inner radius when SCO₂ dry gas seals are operated near the critical point. Whether phase transitions are considered in the model affects the sealing performance seriously. When phase transitions are considered, the sealing performance depends significantly on the working conditions, and unexpected results are produced when inlet conditions approach the critical point.

The numerical model for SCO₂ dry gas seals with phase transitions is established. The phase distribution and the sealing performance of SCO₂ dry gas seals are explored.

The purpose of this paper is to present a three-dimensional finite volume-based analysis on the effects of propeller blades on fountain flow in a wave soldering process and performs an experimental validation.

Solder pot models with various numbers of propeller blades were developed and meshed by using hybrid elements and simulated by using the FLUENT fluid flow solver. The characteristics of the fountain, such as flow profile, velocity vector, filling time, and fountain advancement, were investigated. Molten solder (Sn63Pb37) material, a temperature of 250°C, and a propeller speed of 830 rpm were applied in the simulation. The predicted results were validated by the experimental fountain profile.

The use of a six-blade propeller in a solder pot increased the fountain thickness profile and reduced the filling time. Moreover, a six-blade propeller design resulted in a stable fountain profile and was considered the best choice for current wave soldering processes.

This study provides a better understanding of the effects of propeller blades on the fountain flow in the wave soldering process.

The study explores the fountain flow behavior and provides a reference to the engineers and designers in order to improve the fountain flow of the wave soldering.

The purpose of this paper is to acquire sealing properties of supercritical CO₂ (S-CO₂) T-groove seal under ultra-high-speed conditions by thermo-elastohydrodynamic lubrication (TEHL) analysis.

Considering the choked flow effect, the finite difference method is applied to solve the gas state equation, Reynolds equation and energy equation. The temperature, pressure and viscosity distributions of the lubricating film are analyzed, and sealing characteristics is also obtained.

The face distortions induced by increasing rotational speed leads to the convergent face seal gap. When the linear velocity of rotation exceeds 400 m/s, the maximum temperature difference of the sealing film is approximately 140 K, and the viscosity of CO₂ is altered by 17.80%. Near the critical temperature point of CO₂, while the seal temperature increases by 50 K, the opening force of the T-groove non-contact seal enhances by 20% and the leakage rate declines by 80%.

The TEHL characteristics of the T-groove non-contact seal are numerically analyzed under ultra-high-speed, considering the real gas effect and choked flow effect. In the supercritical conditions, the influence of rotational speed, seal temperature, seal pressure and film thickness on sealing performance and face distortions is analyzed.

The purpose of this study is to determine the sealing performance of face seals by numerical analysis of thermoelastohydrodynamic characteristics of supercritical CO₂ (S-CO₂) spiral groove face seals in the supercritical regime.

The spiral groove face seal was used as the research object. The distribution of lubricating film pressure and temperature was analysed by solving the gas state, Reynolds and energy equations using the finite difference method. Furthermore, the influence law of sealing performance was obtained.

Close to the critical temperature of S-CO₂, face distortions produced by increasing pressure lead to divergent clearance and resulted in reduced opening force. In the state of S-CO₂, the face distortions generated by increasing seal temperature lead to convergent clearance, which enhances the opening force. In addition, near the critical temperature of S-CO₂, the opening force may be reduced by 10%, and the leakage rate of the seal sharply increases by a factor of four.

The thermoelastohydrodynamic characteristics of supercritical CO₂ face seals are illustrated considering the actual gas effect including compressibility, heat capacity and viscosity. Face distortions and sealing performance were calculated under different seal pressures and seal temperatures in the supercritical regime, as well as with N₂ for comparison.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0169/

The purpose of this study is to investigate the sealing performance of S-CO₂ dry gas seals (DGSs) by considering the effects of pressure-induced deformation, thermal deformation and coupling deformation.

A hydrodynamic lubrication flow model of S-CO₂ DGS was established, and the model was solved using the finite difference and finite element methods. The pressure-induced deformation and thermal deformation of the sealing ring, as well as the sealing performance under the effects of pressure-induced deformation, thermal deformation and coupling deformation, were obtained.

The deformation of the sealing ring is mainly thermal deformation. The influence of pressure-induced deformation on leakage and gas film stiffness is greater than that of thermal deformation and coupling deformation. However, thermal deformation has a greater impact on friction torque and minimum film thickness than pressure-induced deformation and coupling deformation. The influence of deformations on sealing performance is important.

The sealing performance of S-CO₂ DGSs was analyzed considering the effect of pressure-induced deformation, thermal deformation and coupling deformation, which can provide a theoretical basis for S-CO₂ DGS optimization design.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0120/

This paper aims to investigate the thermal fluid–structure interactions (FSIs) of printed circuit boards (PCBs) at different component configurations during the wave soldering process and experimental validation.

The thermally induced displacement and stress on the PCB and its components are the foci of this study. Finite volume solver FLUENT and finite element solver ABAQUS, coupled with a mesh-based parallel code coupling interface, were utilized to perform the analysis. A sound card PCB (138 × 85 × 1.5 mm3), consisting of a transistor, diode, capacitor, connector and integrated circuit package, was built and meshed by using computational fluid dynamics pre-processing software. The volume of fluid technique with the second-order upwind scheme was applied to track the molten solder. C language was utilized to write the user-defined functions of the thermal profile. The structural solver analyzed the temperature distribution, displacement and stress of the PCB and its components. The predicted temperature was validated by the experimental results.

Different PCB component configurations resulted in different temperature distributions, thermally induced stresses and displacements to the PCB and its components. Results show that PCB component configurations significantly influence the PCB and yield unfavorable deformation and stress.

This study provides PCB designers with a profound understanding of the thermal FSI phenomenon of the process control during wave soldering in the microelectronics industry.

This study provides useful guidelines and references by extending the understanding on the thermal FSI behavior of molten solder for PCBs. This study also explores the behaviors and influences of PCB components at different configurations during the wave soldering process.

This study aims to determine the minimum force required to pull out a surface mount component in printed circuit boards (PCBs) during the wave soldering process through both experimental and numerical procedures.

An efficient experimental technique was proposed to determine the minimum force required to pull out a surface mount component in PCBs during the wave soldering process.

The results showed that the pullout force is approximately 0.4 N. Comparing this value with the simulated force exerted by the solder wave on the component (≅ 0.001158 N), it can be concluded that the solder wave does not exert sufficient force to remove a component.

This study provides a deep understanding of the wave soldering process regarding the component pullout, a critical issue that usually occurs in the microelectronics industry during this soldering process. By applying both accurate experimental and numerical approaches, this study showed that more tests are needed to evaluate the main cause of this problem, as well as new insights were provided into the depositing process of glue dots on PCBs.

This chapter elaborates a “pedagogy of narrative shifting” as conceptualized by Li, Conle, and Elbaz-Luwisch (2009) in a course that seeks to foster dialogue across difference in an Israeli university located in a highly polarized setting. The approach draws on personal life stories as a vehicle for examining multiculturalism in teacher education, in the context of the multiple and overlapping identities, conflict and narratives of exclusion that characterize Israeli society. For prospective teachers, the opportunity to tell an important personal story and to have that story heard and validated by others, contributed to both personal and professional development. Working with their stories in a small-group format allowed students to develop their own “internally persuasive discourse” (Bakhtin, 1981) in discussions of controversial issues. Prominent themes emerging in the work included “recognition” (Taylor, 1994) and “resonance” (Conle, 1996). Engaging with bodily experience and with the imagination helped participants to transcend limited understandings and create shared visions of their present and future. The course afforded a unique space for dialogue that can be adapted for other contexts, to allow teacher educators to engage with their students in new and creative ways.