Engineering Design Requirements Research Articles

Machine-learning-based capacity prediction and construction parameter optimization for energy storage salt caverns

The construction design and control of energy storage salt caverns is the key to ensure their long-term storage capacity and operational safety. Current experimental and numerical design/optimizing methods are time-consuming and rely heavily on engineering experience. This paper proposes a machine-learning-based method for the rapid capacity prediction and construction parameter optimization of energy storage salt caverns. We propose a data generation method that uses 1253 sets of random construction parameters as input. The resulting capacity/efficiency-concerned effective volume (V) and maximum radius (rmax) obtained by our numerical program are the output. A back-propagation artificial neural network model for salt cavern construction prediction (BPANN-SCCP) is trained on the dataset. The cross-validated mean absolute percentage error (MAPE) of the BPANN-SCCP predicted V is 1.838%, that of the predicted rmax is 3.144%. This accuracy meets the engineering design requirements, and the prediction efficiency is improved by about 6 × 107 times. Using this model, a design parameter optimization method is devised to optimize 3 sets of design parameters from a million random ones. The resulting caverns are regular in shape with larger capacity ratio than 3 field caverns in Jintan Salt Cavern Gas Storage, verifying the reliability of the proposed optimization method.

Design of DC transmission busbar connection of CRAFT

Aiming at the local overheating phenomenon of the contact position caused by the large current operation in the complex environment in the design of the DC transmission busbar of the CRAFT (Comprehensive Research Facility for Fusion Technology) converter power supply, based on the contact resistance measured by a certain contact torque and contact area, this paper proposes a method based on transmission Thermal theory and ANSYS thermoelectric coupling module method. The busbar temperature range is determined by considering and not considering the contact resistance, and the maximum temperature of the flexible connection is obtained through simulation, and the maximum temperature of the flexible connection is obtained by simulation. Finally, the temperature rise experiment was carried out on the linear flexible connection and the L-shaped flexible connection, and compared with the simulation results, it showed a good consistency and met the engineering design requirements.

Validation of Doppler Temperature Coefficients and Assembly Power Distribution for the Lattice Code KYLIN V2.0.

This work is interested in verifying and analyzing the advanced neutronics lattice code KYLIN V2.0. Assembly calculations are an integral part of the two-step calculation for core design, and their accuracy directly affects the results of the core physics calculations. In this paper, we use the Doppler coefficient numerical benchmark problem and CPR1000 AFA-3G fuel assemblies to verify and analyze the advanced neutronics lattice code KYLIN V2.0 developed by the Nuclear Power Institute of China. The analysis results show that the Doppler coefficients calculated by KYLIN V2.0 are in good agreement with the results of other well-known nuclear engineering design software in the world; the power distributions of AFA-3G fuel assemblies are in good agreement with the results of the RMC calculations, it’s error distribution is in accordance with the normal distribution. It shows that KYLIN V2.0 has high calculation accuracy and meets the engineering design requirements.

Filling Treatment of Surface Subsidence Resulted From Underground Mining in a High-Altitude Mine

In the process of filling the goaf of Huashugou copper mine, the filling aggregate was the mine’s self-produced copper flotation tailings. The physical and chemical property tests showed that the tailings were relatively fine, and the cumulative contents of the 7.5, 15, 80, and 90 μm particles were 56.99, 79.46, 99.88, and 100%, respectively. PSA42.5 Portland slag cement was selected as the cementing material for the tests. The amount of finely ground blast furnace slag added to the cement was 20–50%. The filling test blocks of all proportions were demolded within 24–36 h, and the integrity of the formed filling bodies was satisfactory. Among them, the uniaxial compressive strength of the test block formed by the filling slurry with a tailings-to-cement ratio of 3/1 and a concentration of 74% after 3, 7, 28, and 60 days reached 0.833, 2.026, 4.520, and 6.560 MPa, respectively. The strengths of the other filling blocks also met the engineering design requirements. Based on the statistical regression analysis method, the influences of the slag cement content χ₁ and the tailings water content χ₂ on the filling body’s strength Ϭ were analyzed. The regression calculation also considered the interaction between χ₁ and χ₂, and the obtained multiple nonlinear regression model successfully predicted Ϭ. In production and application, the large density of tailings would accelerate their settling, which could easily cause blockage during the transportation of filling slurry through the pipeline. Regarding a series of existing filling materials and technical conditions, the filling process investigated in this study overcomes several unfavorable conditions. Using advanced and reliable technology and an industrial filling pump with a delivery pressure of 10 MPa, the prepared filling slurry concentration was 68–72% and the flow rate was 56–79 m3/h. The tailings and PSA42.5 Portland slag cement combined quite well. The filling body in the goaf demonstrated excellent homogeneity, and the various industrial indicators met the technical requirements for mining deposits. The preparation of high-quality filling materials with a smooth filling process has played a positive role in the prevention and treatment of surface mountain cracks and collapse during underground mining in high-altitude areas.

Performance test of conceptually designed hydraulically suspended passive shut down subassembly for CFR600

Hydraulically Suspended Passive Shutdown Subassembly (HS-PSS) of Sodium-cooled Fast Reactor (SFR), which can protect the reactor from beyond design basis accidents, is especially suitable for responding to the Unprotected Loss of Flow accident (ULOF). In this study, the performance of the conceptually designed HS-PSS for China Fast Reactor with 600 MW electric power (CFR600) that is being developed by the China Institute of Atomic Energy (CIAE) was experimentally investigated. Suspension tests, free drop performance tests, and hydraulic characteristic verification of the HS-PSS were carried out on a specially constructed vertical hydraulic test loop. Furthermore, the hydraulic characteristic data such as suspension critical flow rate, drop time, pressure drop, and hydraulic thrust on the Hydraulically Moving Body (HMB) inside the HS-PSS was obtained to verify whether they meet the design requirements. The HMB prototype has a drop time of 10.65s under the coast-down flow rate, and the initial falling critical flow rate is 1.80 kg/s, at 84 °C. Both agree well with the theoretical calculation results and meet the engineering design requirements.

Research and application of cave slag tailings in concrete

This article starts with the characteristics of cave slag tailings, proposes to optimize the quality of the concrete production process and product structure by improving the composition of concrete fine aggregates, and conducts research on the key technologies of the application of cave slag tailings to concrete. Concrete quality and economic cost are the basic frameworks, and the feasibility of using cave slag tailings is comprehensively analyzed. It has been verified by experiments that the application of cave slag tailings can greatly improve the stability of concrete production process, reduce concrete structural defects and quality disputes caused by process control, and can significantly reduce the cost of single main material of concrete and bring good Economic benefits. At present, the slag tailings of the cave have been widely used in the resettlement houses of Houyu, Minhou, the MIXC# building, TA# building and its basement of the fourth phase of Fuzhou China Resources Vientiane City, and all performances have reached the engineering design requirements.

Optimal off-ramp terminal locating strategy based on traffic safety and efficiency

ABSTRACT Off-ramps are key nodes which connect urban elevated highways and auxiliary roads, and the distance between an off-ramp terminal and an intersection (ORTI-D) relates directly to traffic safety and efficiency. The authors introduced a new off-ramp terminal locating strategy considering traffic safety and efficiency synthetically. After building a basic VISSIM simulation model which included two-lane off-ramp, one-lane auxiliary road before the weaving area and four-lane entrance road before a no-signal intersection, the functional relationships of the LWA (Length of Weaving areas)-TIT (Time integrated time-to-collision) and the LWA-TTD (Total traffic delay) were developed. On this basis, the genetic algorithm was used to obtain the traffic safety-efficiency optimal ORTI-D and a positive correlation between the weaving proportion and the optimal ORTI-D was found. The methods developed in this paper can satisfy the requirements of off-ramps engineering design and contribute to solve traffic safety and efficiency problems in traffic management.

Stabilisation and characterisation of soil using wollastonite powder

In emerging countries like India, foundation extension and advancement request building destinations with soils of predominant attributes as execution of structure fundamentally relies upon the soil conditions. Particularly while raising the structure on feeble soils like expansive soils, it needs most extreme consideration since it terribly influences the execution of the structure by demonstrating high volume change with impact of water content. In order to make the unfortunate expansive soils to achieve geotechnical engineering design requirements, the process of soil stabilization can be applied to improve the strength characteristics of these soils. This study boons the investigation into the improvement of strength characteristics of expansive soils using wollastonite powder as an additive which is naturally available to reduce the cost and other environmental effects. The influence of varying percentages of wollastonite powder in strength increment is observed based on unconfined compression test conducted on two expansive soils with compaction characteristics at varying preserving days of 3, 7, 14 and 28 days. From the compaction test, it was detected that Maximum Dry-density was decreased whereas Optimum Moisture content of soils increased with increase in dosage of admixture. The Unconfined compressive strength values of soils treated with WP increased up on addition of 12.5% wollastonite powder then, a slight decrease was observed. However, this value was higher than the untreated soil up on 15% addition of wollastonite powder. Peak stress was observed to 393.6% and 253.9% as compared to untreated soils on addition of 12.5% wollastonite powder at 28 days of curing. Thus, the results showed that, wollastonite powder was effective additive for soil, which could boost stability and condense the cost of process in addition to improve strength and properties.

Model test of pumping operation of Sanhekou hydro-junction project

Aiming at the pumping operation of Sanhekou Hydropower Station’s pump-turbines, based on model tests, data measurements were performed on the rated speed and variable speed pumping operations. In addition, the efficiency test and hump margin test were implemented, and the corresponding performance curves were obtained. The results meet the engineering design requirements and can provide technical guidance for the speed control of the power station.

Study on turbulence drag reduction of riblet plate in hypersonic turbulent flows

This paper focuses on turbulence drag reduction of riblet plate in hypersonic turbulent flows. We use direct numerical simulation (DNS) and large eddy simulation (LES) to simulate three-dimensional spatially-developing boundary layer over the flat plate and riblet plate with a free-stream Mach number [Formula: see text]. The results reveal the influence of different riblet heights [Formula: see text] and riblet distances [Formula: see text] on drag reduction effect. The drag reduction effect increases with the increase of riblet height and the decrease of riblet distance within suitable range of parameter values. Through analysis, it can be seen that the riblet plate affects the turbulent contribution of the skin friction by suppressing or destroying the large-scale vortex structure. Combined with the actual engineering design requirements, we can use the riblet plate with appropriate parameters to achieve the purpose of turbulence control.

Profile model for management of sustainability integration in engineering design requirements

This research provides insights into how sustainability considerations in engineering product design can be addressed through early stages of requirement management processes. Five key elements for ...

Transversal vibration analysis of the upper span of nonlinear closed-loop track systems

In order to analyze the effect of track pre-tension on the transversal vibration of the upper track, a multibody dynamics model of a tracked vehicle needs to be established. In view of the complex structure of tracked vehicles, the computational efficiency of conventional methods cannot meet engineering design requirements. In this paper, the Riccati Transfer Matrix Method for nonlinear closed-loop multibody systems is proposed and applied to the modeling and simulation of tracked vehicle systems. It avoids the overall dynamic equations of the system and achieves efficient computation with a smaller matrix scale. By selecting accelerations and forces as elements of the state vectors instead of coordinates and forces, linearization is avoided. The track chain is cut in a revolute joint. Its effect on the closed-loop system is represented by a set of constraint equations and internal constraint forces. An improved Riccati transformation for closed-loop systems is proposed to connect the internal force and acceleration parts in the state vector with the system constraint internal forces. The track pre-tension can be adjusted by moving the position of the idler relative to the chassis. The root mean square of vertical acceleration of mid-span with respect to the chassis is selected to evaluate the transversal vibration of the upper track. Simulation of a tracked vehicle driving on different road conditions is carried out with different idler displacements. Finally, a reasonable adjustment strategy for the track tensioner is proposed corresponding to different running conditions.

Induction Brazing Analysis of EAST Fast Control Coil Conductor

To achieve much higher operation parameters of EAST device, some key components are upgraded. Fast control coil as one of the key components is updated by using novel stainless steel mineral insulation conductor and the turns are increased to 4, which means the coil's operation environment becomes more severe and larger loads will be encountered. The coil joint is apt to be destroyed in view of the potential defects during the fabrication. Given the numerous advantages, the induction brazing is being considered for the conductor joint connection. The copper mock up is used to carry out the feasibility analysis. Based on the structural size of copper tube, the brazing parameters are calculated and a 2 turns splitting induction coil is designed. Some influence factors effecting the induction efficiency are analysed. It will provide guidance for choice of power supply and the optimization design of induction coil. In addition, the induction experiment is launched and comprehensive joint performance tests are subsequently performed. The test results indicate the joint overall performance could satisfy the basic engineering design requirement, but also some defects are found and more study should be carried out and to further improve the brazing quality.

Development and Application of a 10 kV Mechanical DC Circuit Breaker

A DC circuit breaker is piece of core equipment for DC grid construction and can achieve fast isolation of DC faults in the grid. In this paper, based on the fault characteristics and protection requirements of an AC/DC hybrid distribution network, the technical parameters and topology structure of an inductance and capacitance (LC) resonant commutation-type mechanical DC breaker are proposed. Furthermore, an engineering prototype of the mechanical DC circuit breaker is developed, then a small current breaking test and a large current breaking test are carried out. The test results show that a 10 kA fault current can be interrupted within 10 ms by the engineering prototype. Finally, the engineering prototype of the mechanical DC circuit breaker is installed in the AC/DC hybrid distribution network project, and a current breaking test is carried out. The test results show that the mechanical DC circuit breaker has good running conditions, and the function and performance meet the engineering design and operation requirements.

A Compensation Method for Deformed Array Antennas Considering Mutual Coupling Effect

The structural deformation of an array antenna could lead to degradation of its radiation performance, thus not meeting the engineering design requirements. There are many methods to compensate for the radiation pattern of deformed array antennas, but seldom do they take the mutual coupling (MC) effect into account. However, the MC effect is one of the important factors that cannot be neglected in practical application. In this letter, the MC effect of an array antenna is analyzed by network theory. In addition, a compensation method is proposed for deformed array antennas based on the electromechanical coupling analysis method and the least squares error approach. This method could be applied for the arrays with single-mode radiating elements. Finally, a numerical example is given to demonstrate the effectiveness of the proposed method.

Approaches to Addressing ABET Engineering Design Requirements

Approaches to Addressing ABET Engineering Design Requirements

Discussion on Electrical Design of Passive Residential Building

As the national buildings in each climate zone and passive low energy consumption building demonstration projects expand, there has been a wave of innovation across the construction industry. China is also becoming a hot zone for energy-efficient and high-performance passive buildings. Along with the traditional passive building structure, steel structure passive construction, assembled PC structure passive construction such as the emergence of various types of passive construction, as well as a variety of new building materials, doors and Windows, and air conditioning air equipment, put forward a new challenge for building electrical engineering design personnel and requirements.

Topology optimisation of adhesive joints using non-parametric methods

This research investigates the applicability of non-parametric structural optimisation algorithms for the optimisation of structural adhesive joints. Three types of adhesive joint; single lap, double lap and double lap strap, were used for the structural optimisation. Evaluation of the non-parametric solver was carried out by first optimising the adherend geometry of the adhesive joints and then including the adhesive fillets in the optimisation domain. Thus, optimisation of single and then multiple material domains was performed. It was noted that most of the structural features of adhesive joints can be optimised by a non-parametric optimiser, however, a few limitations of the solver for adhesive joint applications were also discovered. Engineering judgement may be needed when extracting the optimised geometries for further use. A significant reduction in the stresses in the adhesive layer were observed after the optimisation of all three types of selected joints, indicating the potential of these techniques, however a clear understanding of both the optimization methods and the engineering design requirements and constraints is needed for their effective application for adhesive joints.

Improvement of Quantum-Behaved Particle Swarm Optimization Algorithm and Its Application to Ship Hull Waterlines Approximation Based on Non-Uniform Rational B-Spline

Nowadays, the optimization algorithm used in the ship design is a hot research area. The computation efficiency and stability of the algorithm depended on the number of design variables, the algorithm parameters, and operation process. In order to improve design efficiency and stability, this paper focuses on the waterlines approximation with as less control parameters as possible applying the improved quantum-behaved particle swarm optimization (QPSO) algorithm based on NURBS (Non-Uniform Rational B-Spline). The optimization model is constructed with the homogeneous coordinate component of the fitted waterline's control points as the design variables. The objective function is set to minimize the maximum relative difference between the widths of the approximated waterlines and the original ones corresponding to the same stations. The appropriate constraints are set according to the characteristics of the free segments of the waterline. The QPSO algorithm is used to solve this optimization problem. With view to the correlation among the design variables, the algorithm is improved by introducing the memory factor to ensure the design variables within the feasible region during the evolution process. Based on this improved QPSO algorithm, the waterlines of the full-scale hull form are approximated and the hull surface is constructed using the skinning algorithm with them. Compared with the related reference results, this approximation method has higher precision and can satisfy the engineering design requirements. It is indicated that it is feasible to represent the hull form using the reduced data. Furthermore, the success rate and the average relative difference comparison between the basic QPSO and the improved QPSO show the reliability and stability of the algorithm. This method proposed in this paper provides a foundation for the hull surface design based on the reduced data. Meanwhile, the improved QPSO algorithm can be used in the similar optimization problem with the design variables correlated with each other.

A shortcut algorithm for solving long-term conjugate heat transfer problems based on quasi-steady flow

PurposeThe time of tightly coupled transient calculation and the accuracy of conventional loosely coupled algorithm make it difficult to meet the engineering design requirements for long-term conjugate heat transfer (CHT) problems. The purpose of this paper is to propose a new loosely coupled algorithm with sufficient accuracy and less calculation time on the basis of the quasi-steady flow field. Through this algorithm, it will be possible to reduce the update frequency of the flow field and devise a strategy by which to reasonably determine the update steps.Design/methodology/approachIn this paper, the new algorithm updates the flow field by solving the steady governing equations in the fluid region and by calculating the transient temperature distribution until the next update of the fluid flow, by means of solving the transient energy equations in the entire computational domain. The authors propose a strategy by which to determine the update step, by using the engineering empirical formula of the Nusselt number, on the basis of the changes of the inlet and outlet boundary conditions.FindingsTaking a duct heated by an inner forced air flow heating process as an example, the comparison results for the tightly coupled transient calculation by Fluent software shows that the new algorithm is able to significantly reduce the calculation time of the transient temperature distribution with reasonable accuracy. For example, the respective computing times are reduced to 22.8 and 40 per cent, while the duct wall temperature deviations are 7 and 5 per cent, using the two flow update time steps of 100 and 50 s on the variable inlet-flow rate conditions.Originality/valueThe new algorithm outlined in this paper further improves the calculated performance and meets the engineering design requirements for long-term CHT problems.