Mesh-based Parallel Code Coupling Interface Research Articles

Simulation study of supercritical carbon dioxide jet fracturing for carbonate geothermal reservoir based on fluid-thermo-mechanical coupling model

Geothermal energy is a kind of renewable, sustainable and clean energy resource. Geothermal energy is abundant in carbonate reservoirs. However, low matrix permeability limits its exploitation. The supercritical carbon dioxide (SC–CO2) jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO2 simultaneously. In this paper, we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of SC-CO2 jet fracturing. The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface. The physical properties change of SC-CO2 with temperature were considered in the numerical model. Results showed that SC-CO2 jet fracturing is superior to water-jet fracturing with respect to jetting velocity, particle trajectory and penetrability. Besides, stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO2 jet than that by water jet. Moreover, pressure and temperature control the jet field and seepage field of SC-CO2 simultaneously. Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO2. The key findings are expected to provide a theoretical basis and design reference for applying SC-CO2 jet fracturing in carbonate geothermal reservoirs.

Mechanical properties of CFRP-strengthened prestressed concrete cylinder pipe based on multi-field coupling

Broken prestressing wires in prestressed concrete cylinder pipe (PCCP) can cause incident of pipe burst. A method was proposed to repair damaged PCCP with broken wires by externally bonding carbon fiber reinforced polymer (CFRP). A finite element model was established and calibrated against the data from a prototype-scale laboratory test. Upon calibration, a three-dimensional numerical model was built to simulate the response of PCCP pipeline with five segments. Multi-field coupling was accomplished by Mesh-based parallel Code Coupling Interface (MpCCI) to incorporate the soil–pipe interaction and the effect of hydrodynamic pressure for PCCP. The effect of externally bonded CFRP to repair PCCP with broken wires was systematically analyzed. Results show that at a certain number of broken wires, the use of CFRP for pipe repair can significantly reduce the strains for each pipe component and increase the resilience of PCCP. The improved PCCP performance was assessed on the basis of crack visibility in the concrete core, and the deformation of the steel cylinder. The CFRP strain was much less than its ultimate strain, when cracks in the concrete core became visible and the steel cylinder yielded, suggesting that failure of PCCP could be ahead of CFRP.

Mechanical responses of bell‐and‐spigot joints in buried prestressed concrete cylinder pipe under coupled service and surcharge loads

AbstractPrestressed concrete cylinder pipe (PCCP) is widely used in hydraulic engineering. The bell‐and‐spigot joint is a weak point along a PCCP pipeline, since damage of joint can affect the operation of the whole pipeline. In this paper, a three‐dimensional numerical model of buried PCCP, considering the simulation of rubber gasket in bell‐and‐spigot joint is established. The fluid–structure coupling of PCCP is accomplished using the Mesh‐based parallel Code Coupling Interface (MpCCI), where the pipe and the surrounding soil are characterized in the software ABAQUS, and the pressurized water is modeled in the software FLUENT. The force and rotation angle at joints of PCCP under different conditions, including surcharge load, loading location, cover depth, and internal pressure, are analyzed. It is shown that the rotation angle of joint exceeds the allowable value, when the surcharge load is greater than 180 kPa. Compared with the effect of surcharge load, the offset distance (i.e., distance between the loading position and the pipe axis) has a greater influence on the development of horizontal displacement and rotation angle. As the offset distance increases, both the horizontal displacement and rotation angle at joints increase first, and they decrease after the peak.

Mechanical sensitivity analysis of pipe-liner composite structure under multi-field coupling

Cured-in-place pipe (CIPP) has become one of the most widely used pipeline trenchless rehabilitation technologies because it has the advantages of needing no grouting, rapid curing, and short construction time. However, previous research has not yet revealed the mechanical sensitivity of pipe-liner composite structures. In this paper, a numerical model for a pipe-liner composite structure under multi-field coupling of the traffic load, earth pressure and water flow was first established based on an Abaqus, Fluent and mesh-based parallel code coupling interface (MpCCI). Then, the maximum principal stress of the pipeline, vertical displacement of the pipeline, von Mises stress of the CIPP liner and vertical displacement of the CIPP liner were selected as evaluation indicators, and the CIPP thickness, cover depth, traffic load, corrosion width, corrosion depth, and water quantity were selected as sensitive factors of the pipe-liner composite structure. Finally, the mechanical characteristics of the pipe-liner composite structure were analysed under condition of different sensitive factors; moreover, the sensitivity of the sensitive factors was ranked based on the sensitivity coefficient. The research results are consistent with previous research providing a theoretical basis for the optimal design of wall thicknesses for CIPPs.

Thermal-fluid-structure coupling analysis for plate-type fuel assembly under irradiation. Part-I numerical methodology

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect its stress conditions, mechanical behavior and thermal-hydraulic performance. A reliable numerical method is of great importance to reveal the complex evolution of mechanical deformation, flow redistribution and temperature field for the plate-type fuel assembly under non-uniform irradiation. This paper is the first part of a two-part study developing the numerical methodology for the thermal-fluid-structure coupling behaviors of plate-type fuel assembly under irradiation. In this paper, the thermal-fluid-structure coupling methodology has been developed for plate-type fuel assembly under non-uniform irradiation condition by exchanging thermal-hydraulic and mechanical deformation parameters between Finite Element Model (FEM) software and Computational Fluid Dynamic (CFD) software with Mesh-based parallel Code Coupling Interface (MpCCI), which has been validated with experimental results. Based on the established methodology, the effects of non-uniform irradiation and fluid were discussed, which demonstrated that the maximum mechanical deformation with irradiation was dozens of times larger than that without irradiation and the hydraulic load on fuel plates due to differential pressure played a dominant role in the mechanical deformation.

Mechanical Response of Gasketed Bell-and-Spigot Joint of Concrete Pipeline under Multifield Coupling

Concrete pipe may suffer joint failure under the coupling effect of internal fluid and overlying load, which may lead to pipe leakage. Based on Abaqus and Fluent finite element software, a three-dimensional refined model of drainage pipeline with gasketed bell-and-spigot joints and flow field model inside the pipeline was established. Fully considering the compression of the gasket during pipeline assembly and pipe-soil interaction, the fluid-structure coupling numerical simulation was carried out by using the MpCCI (Mesh-based parallel Code Coupling Interface) platform, and the mechanical response of the concrete pipe joint under the multifield loads coupling effects of burial condition, traffic load, and internal fluid was studied. The accuracy of the coupling model was verified through the full-scale tests that have been carried out. The influences of various factors on the circumferential stress and vertical deformation of the joint were mainly studied. The result reveals that the influence of different working conditions on the circumferential stress of the pipe joint is mainly concentrated on the crown and the invert of the joint, the areas vulnerable to tensile damage. The change of flow field leads to a slight difference in the vertical deformation of the joint, while variation in gasket hardness and cushion compactness has a certain influence on the vertical deformation of the joint. The change of buried depth has a negative correlation to the vertical deformation of the joint, and the change of load position has a significant nonlinear effect. The result provides a theoretical basis for further research on the mechanical mechanism of the pipeline joints during operation.

Parameter Analysis of Wall Thickness of Cured-in-Place Pipe Linings for Semistructured Rehabilitation of Concrete Drainage Pipe

Frequent accidents caused by underground pipeline damage are a widespread societal concern. Trenchless rehabilitation methods, particularly cured-in-place pipe (CIPP) lining, are increasingly used for pipeline repair with great success. Existing research is mainly concerned with practical improvements in rehabilitation and evaluating the performance of rehabilitation. In this study, the model of corroded buried concrete pipeline that had been rehabilitated with CIPP was established using numerical methods, and the Mesh-based parallel-Code Coupling Interface (MpCCI) was used to investigate multifield coupling effects of soil pressure, traffic load, and fluid-structure interactions. Moreover, the influences of corrosion depth, corrosion width, traffic load, cover depth, and water quantity on CIPP wall thickness were compared and analyzed. The result shows that maximum principal stress and vertical displacement of pipeline markedly decreased after CIPP rehabilitation, and thus the new CIPP can carry loads in a deteriorated pipe. Stress and displacement of the composite pipe liner were positively correlated with corrosion depth and negatively correlated with corrosion width. Increase in traffic load rapidly increases von Mises stress of CIPP, and increase in cover depth rapidly increases maximum principal stress of pipeline. Water flow has little effect on the pipe liner, and flow capacity increases slightly after CIPP rehabilitation. CIPP wall thickness was positively correlated with corrosion depth, traffic load, cover depth, and water quantity and negatively correlated with corrosion width.

Suppression and utilisation of aeroelastic behaviour in turbine-based combined cycle inlet

This study develops a two-way loosely coupled aeroelastic analysis framework based on a finite-volume fluid solver, a nonlinear finite-element solid solver and the Mesh-based parallel Code Coupling Interface. Research focuses on aeroelastic behaviour in a turbine-based combined cycle inlet after verifying the fluid solver and the coupling strategy through three benchmarks consisting of the inlet experimental model, the classical panel flutter problem and the deformation of a cantilever plate subjected to a shock tube flow. Coupling calculation shows that structural damping is limited only to the vibration suppression of deformable components under constant backpressure but exerts no evident influence on flow field oscillation induced by splitter plate vibration or perturbation from downstream dynamic backpressure. Interestingly, panel deformation (or forced vibration) has a positive impact on the stabilisation of the flow field. The use of a flexible panel with low thickness (e05) successfully prevents the shock train from transitioning, stabilising the performance profiles at the outlet even under dynamic backpressure. Pressure adjustment in the potentially unstable region through panel deformation is assumed to be the solution to weakening the disturbance from splitter plate vibration, which differs from the energy transfer theory under dynamic backpressure that is often found in the literature.

Airflow disturbance induced by coal mine outburst shock waves: A case study of a gas outburst disaster in China

We explore the magnitude of airflow disturbance in mine roadways induced by gas outburst shock waves. Outburst shock wave propagation in the near-field of the outburst source is established and simulated in three dimensions using FLUENT. The effects in connected but distal roadways are represented by a simplified one-dimensional network model and solved by Flowmaster. A Mesh-based Parallel Code Coupling Interface (MPCCI) is applied to couple the three-dimensional (near source) model and the one-dimensional (distal) model. The coupled model is verified by theoretical analysis and against observations from a coal and gas outburst incident comprising 2887 tonnes of coal that occurred in the Jiulishan coal mine, China and general characteristics of outburst events explored. Simulations demonstrate that airflow disturbance induced by outburst shock waves in the coal mine is principally controlled by the shock wave overpressure and fan pressure provided by the main fan. Of these, the shock wave overpressure exerts the dominant impact. The larger the shock-wave overpressure, the more rapid the decrease of airflow in the roadway branches and the larger the ultimate airflow decrease. Furthermore, the arrival time of the minimum air flow rate is delayed. When the fan pressure is large, the ability to resist airflow disturbance is enhanced and the area subject to countercurrent flow is reduced. The initial air flow rate and the restored air flow rate show less correlation with the shock wave overpressures. However, they are both significantly affected by the pressure of the main fan. This work presents a novel approach for the study of airflow disturbance in underground ventilation networks in coal mines caused by coal and gas outbursts and provides guidance for the design of outburst prevention facilities.

Mechanical Response and Parametric Sensitivity Analyses of a Drainage Pipe under Multiphysical Coupling Conditions

Current research was not dedicated to investigate the mechanical behavior of a concrete drainage pipe under multiphysical coupling conditions of overburden pressure, traffic loads, groundwater, and pipe fluids. This study proposes a new numerical solution method for coupled stress, seepage, and flow fields based on a validated finite element model. The model was developed by ABAQUS and FLUENT and then solved simultaneously using the MpCCI (mesh-based parallel-code coupling interface) platform. Results show that the tensile stress at the springline and the radial displacement at the crown (or invert) of the bell under the effect of groundwater alone were reduced by 50.5% and 38.1%, respectively, compared to the effect of traffic load alone. Parametric analyses show that vehicle speed and fluid height have a slight impact on the pipes. The soil cover depth, wheel pressure, and gasket strength are directly proportional to the pipe stress and vertical displacement. Within the scope of their respective changes, the pipe stresses were increased by 34.4%, 36.7%, and 28.5%, and the vertical displacements were increased by 124%, 95.85%, and 87.7%. The bedding and backfill strengths are proportional to the pipe stress and inversely proportional to the vertical displacement. Within the scope of their respective changes, the pipe stresses were increased by 18.2% and 20.0%, and the vertical displacements were decreased by 11.4% and 10.4%. Sensitivity analyses show that soil cover depth has a greatest impact on the pipe, followed by traffic load.

A transient fluid-thermo-structural coupling study of high-velocity LN2 jet impingement on rocks

The high-velocity liquid nitrogen (LN2) jet is an efficient rock breaking method that can be applied in improving drilling rate and enhancing stimulation performances of fossil fuel and geothermal reservoirs. To determine the cooling effect during LN2 jet impingement, a transient fluid-thermo-structural coupling study was conducted in this paper. We adopted a loose coupling method in which the fluid domain and the structure domain are simulated by FLUENT and ABAQUS, respectively, and coupling quantities were exchanged across the fluid-structural interface in every real time increment through the Mesh-based Parallel Code Coupling Interface (MpCCI) server. The v2-f model was employed to calculate the flow field and heat transfer in the fluid domain, and changes of thermo-physical properties of fluid and solid with temperature were considered in the calculation. This model was validated by comparing the simulation results with previous experimental data. According to our simulation results, the velocity and turbulence intensity of LN2 jet are significantly greater than those of water jet under the same conditions. The process of high-velocity LN2 jet impingement can be divided into two stages: (1) the jet impact dominated stage and (2) the thermal dominated stage. In the former stage, stress distributions under the impacts of water jet and LN2 jet are similar. A compressive zone surrounded by a ring tensile stress zone is generated on the impact surface. In the latter stage, the compressive stress near the stagnation point transfers to tensile stress gradually under the effect of LN2 cooling. The LN2 jet induces higher tensile and shear stress in rock, and thus can achieve better rock-breaking performances than water jet. Increasing the rock temperature can further improve the stress magnitude in rock, which makes the rock-breaking performances of LN2 jet more significant.

Numerical simulation and full-scale test on dynamic response of corroded concrete pipelines under Multi-field coupling

Urban concrete pipelines that have been used for a long time after heavy rains are highly prone to accidents under the actions of overlying loads and traffic loads, such as road collapses, pipeline explosions, and so on. However, the mechanical response of concrete pipelines under multi-field coupling has not been revealed. Based on ABAQUS 6.14-1 and FLUENT 16.0, 3-D models of the normal and corroded pipelines and fluid were established, the “true” multi-field coupling was realized in real meaning by MpCCI (Mesh-based parallel-Code Coupling Interface) software, and a full-scale test to verify the numerical method was carried out. On the basis of investigating the dynamic response of normal concrete pipelines under multi-field coupling of earth pressure, traffic load, and FSI (Fluid-Structure Interaction), the parametric and sensitivity analysis of factors (flow rates, roughness, corrosion depths, corrosion widths, and corrosion lengths) affecting the dynamic response of corrosion pipelines were implemented. The results reveal the effect of multi-field coupling on the dynamic response of corroded concrete pipelines. The factors that have the greatest impact on corroded concrete pipelines were pointed out. The good agreement between the results of the full-scale test and the numerical method indicates that the model and the multi-field coupling method developed in this paper are reliable. This study provides a new idea for the study of the mechanical response of buried pipelines under multi-field coupling.

Aeroelastic Study of the Splitter Plate in Turbine-Based Combined-Cycle Inlet

A two-dimensional over–under turbine-based combined-cycle inlet system that exhibits the fluid–structure interaction phenomenon is investigated at both design and off-design states. The mesh-based parallel code coupling interface is used to perform a two-way loosely coupled data exchange across the fluid–structural interfaces. Results indicate that, although the performance variation is limited at a ramjet mode with , unexpected limit cycle oscillations appear accompanied by unsteady amplitudes. Moreover, a remarkable unstart delay along with the deceleration process of performance deterioration can be observed when the backpressure goes through a rapid increase, where the upward deformation of the splitter plate plays a significant role in resisting the downstream disturbance. In contrast, the fluid–structure interaction effect leads to an earlier occurrence of inlet unstart when the angle of attack varies periodically, and it induces limit cycle oscillations at a higher varying frequency. The study reveals the necessity of attaching more importance to the aeroelastic behavior of the splitter plate in the future research and operation of the over–under turbine-based combined-cycle inlet system.

Influence of printed circuit board thickness in wave soldering

This paper presents a thermal fluid–structure interaction (FSI) study of printed circuit boards (PCBs) during wave soldering. The influences of PCB thickness on displacement, stress and temperature distribution are the foci of the study. Five PCB thicknesses (i.e., 0.6, 1.0, 1.6, 2.4, and 3.1 mm) are considered. The paper focuses on a simple PCB with a single hole and constructed in a three-dimensional model. The thermal FSI of the PCB is solved by fluid (FLUENT) and structure (ABAQUS) solvers that are connected using the mesh-based parallel code coupling interface method. Molten solder advancement is tracked using volume-of-fluid technique in the thermal fluid analysis. ABAQUS solves PCB displacement, von Mises stress, and temperature distributions when high solder temperature is experienced during wave soldering. The correlations of PCB thickness to displacement, von Mises stress, temperature distribution, and molten solder filling time are studied. Results reveal that an increase in PCB thickness yields a linear correlation to solder filling time. Temperature distribution, von Mises stress, and displacement of PCB exhibit polynomial behavior to PCB thickness. A laboratory-scale two-way wave-soldering machine is also used to measure PCB temperature during wave soldering. The predicted temperature of PCB is substantiated by the experimental results.

Heat transfer enhancement by flexible printed circuit board's deformation

Flexible printed circuit board (FPCB) has started replacing rigid PCB in some electronic application. However, the deflection and heat transfer of FPCB caused by flow and thermal are far more crucial compared to rigid PCB. In the current study, effects of flow and thermal induced deflection were coupled in real time. The numerical modelling was executed using FLUENT and ABAQUS, coupled online by Mesh-based Parallel Code Coupling Interface (MpCCI). The numerical findings have been validated with experimental results. Rigid PCB with same thermal properties of FPCB has been compared. The findings showed that the deflection of the FPCB does help to increase the heat transfer of the PCB. Furthermore, models with different power of heat sources along with various Reynolds numbers (Re) had been studied. The results exhibited that the magnitude and the trend lines' pattern of deflection divided by characteristic length changes according to thermal power. It indicates both flow and heat have significant effect to the deflection and Nusselt number (Nu) of FPCB. Therefore, flow and thermal should be coupled at the same time for more realistic FPCB simulation under flow environment in operating condition.

Experimental and numerical investigation of flow and thermal effects on flexible printed circuit board

The desire of flexibility, compact, lightweight and low cost in current electronic device increases the application of flexible printed circuit board (FPCB). However, FPCB would encounter significant deflection and stress under operating condition (thermal factor) with air flow cooling system as compared to rigid printed circuit board (RPCB). Therefore, present study aims to investigate the effects of airflow rate and heat on FPCB attached with a ball grid array (BGA) package using experimental and numerical method. In this present study, the simulation was carried out by using FLUENT and ABAQUS, coupled in real time by Mesh-based Parallel Code Coupling Interface (MpCCI) where flow and thermal effects were coupled simultaneously. The experiments were conducted in a wind tunnel with the BGA package on the FPCB. Low discrepancy between simulation and experimental results indicated that the proposed numerical simulation method is proven to be reliable and sufficient to study the FPCB with thermal and flow effects which has not been established by previous researchers. The findings also showed that the Reynolds number and heat have significant effects on FPCB's deflection and stress. Therefore, it is important to include thermal effect when dealing with FPCB under flow environment. The outcomes of this paper can be a guideline to the FPCB industries.

Influence of Material Properties on the Fluid-Structure Interaction aspects during Molded Underfill Process

This paper presents the investigation of the effects of epoxy moulding compound’ (EMC) viscosity on the FSI aspects during moulded underfill process (MUF). Finite volume (FV) code and finite element (FE) code were connected online through the Mesh-based Parallel Code Coupling Interface (MpCCI) method for fluid and structural analysis. The EMC flow behaviour was modelled by Castro-Macosko model, which was written in C language and incorporated into the FV analysis. Real-time predictions on the flow front, chip deformation and stress concentration were solved by FV- and FE-solver. Increase in EMC viscosity raises the deformation and stress imposed on IC and solder bump, which may induce unintended features on the IC structure. The current simulation is expected to provide the better understandings and clear visualization of FSI in the moulded underfill process.

Fluid-thermal analysis of aerodynamic heating over spiked blunt body configurations

When flying at hypersonic speeds, the spiked blunt body is constantly subjected to severe aerodynamic heating. To illustrate the thermal response of different configurations and the relevant flow field variation, a loosely-coupled fluid-thermal analysis is performed in this paper. The Mesh-based parallel Code Coupling Interface (MpCCI) is adopted to implement the data exchange between the fluid solver and the thermal solver. The results indicate that increases in spike diameter and length will result in a sharp decline of the wall temperature along the spike, and the overall heat flux is remarkably reduced to less than 300W/cm2 with the aerodome mounted at the spike tip. Moreover, the presence and evolution of small vortices within the recirculation zone are observed and proved to be induced by the stagnation effect of reattachment points on the spike. In addition, the drag coefficient of the configuration with a doubled spike length presents a maximum drop of 4.59% due to the elevated wall temperature. And the growing difference of the drag coefficient is further increased during the accelerating process.

Optimization of pin through hole connector in thermal fluid–structure interaction analysis of wave soldering process using response surface methodology

This paper presents an optimization of pin through hole (PTH) connector in the wave soldering process; the optimization was performed by using response surface methodology. The geometrical and process parameters (i.e., offset position, pin diameter, offset angle, and solder temperature) were optimized by using response surface methodology via central composite design for the wave soldering process. Thermal fluid–structure interaction aspects were considered in the optimization. A mesh-based parallel code-coupling interface was employed to connect both fluid and structural solvers. The interactive relationship between independent variables (i.e., offset position, pin diameter, offset angle, and solder temperature) and the responses (i.e., filling time at 75% volume, von Mises stress, and maximum displacement) were investigated. The generated empirical models were examined and well substantiated by the simulation results. The optimum geometrical and process parameters of the wave soldering process for the PCB and PTH connector were as follows: 0.12mm of PTH offset position, 0.17mm of PTH diameter, 0° of offset angle, and 473K of molten solder temperature.

Fluid–structure interaction study of the splitter plate in a TBCC exhaust system during mode transition phase

Splitter plate plays an important role in a turbine-based combined-cycle (TBCC) exhaust system during the mode transition phase when turbojet engine and ramjet engine operate simultaneously. Dissimilar pressure distribution on both sides of the plate has a potential origin in the aeroelastic coupling, which is an interesting topic while few research works have devoted to that aspect. To better understand the aeroelastic behavior of the plate and the corresponding dynamic flow features, an integrated fluid–structure interaction simulation is conducted under one particular operation condition during mode transition phase in the TBCC exhaust system. A finite-volume-based CFD solver FLUENT is adopted to solve the unsteady Reynolds average Navier–Stokes equations. ABAQUS, a finite-element-method-based CSD solver, is employed to compute the plate elastic deformation. A two-way interaction between the fluid and the structure is accomplished by the mesh-based parallel-code coupling interface (MpCCI) in a loosely-coupled manner. The accuracy of the coupling procedure is validated for the flutter of a flat plate in supersonic flow. Then, features of steady flow field of the TBCC exhaust system are discussed, followed by the investigation of the aeroelastic phenomenon of the splitter plate and the evolution process of the flow field pattern. Finally, performances variation of the exhaust system is obtained and discussed. The results show that the plate vibrates with decaying amplitude and reaches a dynamic stable state eventually. The thrust, lift and pitch moment of the TBCC exhaust system are increased by 0.68%, 2.82% and 5.86%, respectively, compared with the corresponding values in steady state which does not take into account the fluid–structure interaction effects. The analysis reveals the importance of considering the fluid–structure interaction effects in designing the splitter plate in the TBCC exhaust system and demonstrates the availability of the present coupled CFD/CSD method as a tool to predict the aeroelastic phenomenon in the TBCC exhaust system.