Flow Design Optimization Research Articles

Study on the structure parameters and design method optimization of blade-type screw steel pipe pile

The rationality of structure parameters of the blade-type screw steel pipe pile is the major factor in determining the safety, applicability, and economy of a pile foundation, but the existing design methods have not defined the specific approaches to calculating structure parameters of blades and steel pipes. To address this issue, an analysis of the strength theory was performed on spatial helical blades, revealing the ratio of blade width to steel pipe radius as the core index to do the structure parameters design of blade-type screw steel pipe pile and established a mathematical calculation model between the vertical bearing capacity of single pile and a. The rational value of a is 2.0–3.0 using numerical calculation. The correlation between blade thickness and wall thickness of steel pipes was determined using the force analysis based on the synergy between blades and steel pipes. Then the structure parameters design method of blade-type screw steel pipe pile with coordinated parameters was proposed. The rationality and superiority of this design method were verified by comparing the existing test data and the finite element simulative analysis. Based on this design method and the current specifications, such as the Technical Code for Building Pile Foundations, a safe, applicable, and economical optimization design method and flow of blade-type screw steel pipe piles were further proposed for engineering design reference.

Optimization Design and Internal Flow Characteristics Analysis Based on Latin Hypercube Sampling Method

Optimization Design and Internal Flow Characteristics Analysis Based on Latin Hypercube Sampling Method

Ripple-Response Modeling and Design-Oriented Analysis of Output Common Power Flow Regulation in Bipolar SIDO DC–DC Converters

Compared with unipolar SIDO DC-DC converters, the output common power flow in the bipolar SIDO DC-DC converters affects lots of system characteristics in high-frequency (HF) region, which poses great challenges for the modeling and design of the bipolar SIDO converters. In this paper, a ripple-response model of the bipolar SIDO DC-DC converter is proposed to capture the HF characteristics by analyzing the response nature and the sampling process of the multi-piecewise current ripple. Based on the derived model, the design-oriented analysis with the change of some key parameters is presented to guide the system optimal design and power flow regulation. Then, the compensators are optimized to improve the dynamical performance and the HF stability simultaneously. Furthermore, the cross-regulation of the SIDO converter is explored via the common- and differential-mode transfer functions. Particularly, the effect of the output common power flow on the cross-regulation is revealed by identifying the frequency-domain coupling point. These analysis results help to suppress the cross-regulation significantly. Finally, the effectiveness of the model and analysis is verified by experimental results. These results show that the proposed method is more suitable for the bipolar SIDO converters to improve power flow regulation in comparison with the existing ones.

Parameters Influences Analysis and Optimization Design Method for Synchronous Transformer of Switched-Capacitor MMC-SST

In the switched-capacitor-based modular multilevel converter-solid state transformer scheme, the switched-capacitor circuit plays a key role in power transfer, electric isolation, voltage clamping, and low-frequency voltage ripple decoupling. However, the operational performances of switched-capacitor circuits are depended on the distribution parameters of synchronous transformers. To explore the parameter constraints, the mathematical model is established, the relationship between the active power transmission capacity and the transformer time constant is studied, the dynamic inrush current stress is also given. The analysis results show that the distribution resistance should be minimally designed to reduce the voltage clamping error, however, a large distribution resistance is good for suppressing the inrush current. Moreover, if the distribution resistance is large and the leakage inductance is small, the time constant is small, which benefits the power transfer. So, there are some contradictions in the transformer design, which needs to make a tradeoff. For coordinating the parameter optimization, the design criteria and influence factors of distribution parameters for the synchronous transformer are analyzed. Then the transformer optimization design flow considering distribution parameter constraints is proposed. Finally, the toroidal transformer prototype and the switched-capacitor experimental platform are developed to verify the correctness of the proposed scheme.

Optimization Design and Internal Flow Analysis of Prefabricated Barrel in Centrifugal Prefabricated Pumping Station with Double Pumps

In order to improve the hydraulic performance of the centrifugal prefabricated pumping station and improve its internal flow pattern, this paper optimizes the geometric model of the centrifugal prefabricated pumping station based on the orthogonal optimization method. Through the subjective analysis method and range analysis method, it is concluded that the primary and secondary order affecting the hydraulic performance of the prefabricated pumping station is: center distance Y, pump spacing S, inlet radius R, suspension height Z, inlet height H, and the optimal parameter combination is pump spacing 550 mm (5.5 d), The suspension height is 300 mm (3.0 d), the center distance is 100 mm (1.0 d), the inlet height is 700 mm (7.0 d), and the inlet radius is 75 mm (0.75 d). The orthogonal optimization results show that under the design condition (Qd = 33.93 m3/h), the efficiency of the centrifugal prefabricated pumping station is 64.69%, which is increased by 0.70%, compared with the initial scheme. The head is 8.76 m, which is increased by 0.10 m, compared with the initial scheme. After optimization, the recirculation vortex at the water inlet of the prefabricated pumping station is smaller than that before optimization, the flow velocity uniformity in the prefabricated barrel is improved, and the flow field is more stable. The research results of this paper can provide theoretical guidance and engineering reference value for the same type of prefabricated pumping stations.

Optimization design and unsteady flow analysis of stall characteristics in a vertical centrifugal pump

Abstract In this paper, an optimization design of the vertical centrifugal pump with vaned diffuser was accomplished, and analyzed the internal flow pattern of the model before and after optimization under stall conditions to explore the relationship between design parameters and the stall characteristics. The reasons for the improvement of efficiency and hump characteristics curve after optimization were revealed combined with streamline distributions, entropy production theory and pressure fluctuation. The results show that the error between the external characteristic result calculated by Computational Fluid Dynamics (CFD) and the experimental value is less than 5%, which proves the reliability of the numerical simulation method adopted in this paper. The hydraulic efficiency under multiple operating conditions and stall characteristics of the optimized model have been significantly improved. After optimization, the entropy production rate in the vaned diffuser is greatly reduced, and the improvement of the internal flow pattern in the vaned diffuser is the main reason for slowing down the hump characteristic curve. The hydraulic performance and the stall characteristics of the vertical centrifugal pump can be significantly improved by properly increasing the radial distance of the vaneless region. The matching relationship between the vaned diffuser and the impeller is one of the important factors that affect the stall characteristics. The large-scale vortices in the vaned diffuser is the main reason for the low-frequency pressure fluctuation signal when operating in the hump region. The low-frequency signal in the vaned diffuser of the optimized model is obviously weakened.

Research on aerodynamic optimization design method and flow mechanism of a high-subsonic compressor cascade

Designing the high-performance, high-subsonic airfoils suitable for different Reynolds number flow is the major challenge for high-altitude long-endurance drones and ultra-high altitude solar aircraft. To overcome the difficulties, this paper proposed a set of aerodynamic optimization design methods that combine the improved category shape function transformation method, parallel computational fluid dynamics, and an improved whale optimization algorithm. This approach achieves high modeling accuracy, computational efficiency, and strong optimization ability. Verification using single-peak, multi-peak, and fixed-dimensional test functions demonstrates that the improved whale optimization algorithm has significantly enhanced optimization capabilities compared with the conventional whale optimization, particle swarm optimization, and gravity search algorithms. Numerical simulations are used to analyze the internal flow mechanisms before and after airfoil optimization under different Reynolds numbers. The results show that, compared with the original airfoil, the optimized airfoil has front loading characteristics that effectively reduce the adverse pressure gradient of the rear part of suction surface, promoting the transition in this region. The reduced adverse pressure gradient also inhibits the development and growth of laminar separation bubbles and slows down the growth of the boundary layer displacement thickness, thereby reducing wake mixing loss and improving the aerodynamic performance.

Neural network-based cooling design for high-performance processors

SummaryUltra-high chip power densities that are expected to surpass 1-2kW/cm2 in future high-performance systems cannot be easily handled by conventional cooling methods. Various emerging cooling methods, such as liquid cooling via microchannels, thermoelectric coolers (TECs), two-phase vapor chambers, and hybrid cooling options have been designed to efficiently remove heat from high-performance processors. However, selecting the optimal cooling solution for a given chip and determining the optimal cooling parameters for that solution to achieve high efficiency are open problems. These problems are, in fact, computationally expensive because of the massive space of possible solutions. To address this design challenge, this article introduces a deep learning-based cooling design optimization flow that rapidly and accurately converges to the optimal cooling solution as well as the optimal cooling parameters for a given chip floorplan and its power profile.

Optimization Design and Internal Flow Field Study of Open‐Design Vortex Pump

To determine the influences of the main structural parameters on open‐design vortex pump performance, optimize the vortex pump performance, and reduce the running vibration and improve stability, orthogonal testing method was introduced in this paper. The selected main factors included impeller outer diameter (D2), impeller outlet width (b2), outlet setting angle of impeller (β2), and inlet setting angle of impeller (β1), and the nine types of impellers were coded according to orthogonal table. After obtaining the preliminarily optimum value range for each factor through range analysis, comprehensive analysis was employed based on the orthogonal test to investigate the main factors and identify the primary and secondary influencing factors affecting the performance of the vortex pump. An optimization scheme was obtained for further design. The results show that the numerical calculation results of the optimization scheme pump are in good agreement with the test results, and it shows the feasibility of the numerical calculation method. The testing results showed that efficiency and head of the optimal model were 4.2% and 9 m higher than those of the prototype model, respectively. Improved efficiency and head met the design requirements. The orthogonal testing method proved the feasibility of performance optimization of the vortex pump. The backflow occurs at the pump entrance and rotates in the same direction with impeller. It moves along the pipe wall from the lateral cavity to the inlet and encourters with the approaching flow.

An Electromagnetic Translational Vibration Energy Harvester Fabricated in MP35N Alloy

This paper presents a mechanically-robust high-power-density electromagnetic vibration energy harvester fabricated from MP35N alloy. Its primary focus is on the use of MP35N alloy, and the corresponding performance. It follows our prior work on a similar harvester fabricated in silicon that now provides a performance baseline. The optimized design flow developed in our prior work is applied here, yielding mechanical, electrical, and magnetic design decisions, and harvesting performance, that remain largely unchanged. Importantly, while supporting comparable harvesting performance, the new material significantly improves robustness and ruggedness as needed for practical applications. The MP35N harvester suspension is fabricated using a combination of water-jet and electrical-discharge machining. The resulting harvester has an active volume of 1.81 cm3, and an output power $P_{Out}$ of 1.26 mW at 1.08 g and 107.7 Hz under matched load. This yields a power density (PD) of 0.7 mW/cm3 and a normalized power density (NPD) of 0.6 mW/cm3/g2. Importantly, the new harvester survives a 6-foot drop, and ordinary handling during fabrication and operation. The addition of backiron is shown to reduce magnetic-path reluctance, increase magnetic coupling, and thus increase output power. The harvester with backiron has an active volume of 2.17 cm3, and a $P_{Out}$ of 2.2 mW at 1.3 g under matched load, yielding a PD of 1.01 mW/cm3 and an NPD of 0.6 mW/cm3/g2. [2020-0261]

Design and Optimization of Bidirectional Tunable MEMS All-Silicon Evanescent-Mode Cavity Filter

This article presents a bidirectional electrostatic MEMS tuner that enables active voltage compensation of integrated evanescent-mode cavity-based tunable filters. Unlike conventional tunable resonators tuned by unidirectional electrostatic diaphragms, the bidirectional design can compensate for residual displacement errors. This corrective tuning can successfully counterbalance long-term viscoelastic relaxation commonly found in large-displacement MEMS diaphragms. Consequently, it can significantly improve stability and reliability without introducing fabrication complexity. A detailed RF-MEMS codesign and a specific optimization design flow are also discussed. A proof-of-concept, two-pole filter is fabricated, which demonstrates a measured bidirectional tuning range of 18.9–39.6 GHz. The forward (main) actuation tunes the filter from 21.3 to 39.6 GHz with 120 V, whereas the reverse (corrective) actuation tunes it from 21.3 down to 18.9 GHz with 2 V. The measured filter insertion loss varies from 3.14 to 0.78 dB. The extracted unloaded quality factor is 265–510, which is comparable with the state-of-the-art unidirectional filters of this type.

Optimal synchronous vibration control for magnetically suspended centrifugal compressor

Abstract The rotor mass imbalance is common in rotating machinery, which can lead to the synchronous vibration in the magnetically suspended centrifugal compressor (MSCC) system. This work proposes a synchronous vibration control method based on the optimal notch filter. Firstly, the dynamics of the magnetically suspended rotor (MSR) system with mass imbalance is modeled. Then phase-shift notch filter for the synchronous vibration suppression is designed according to theoretical stability analysis of the whole system. Furthermore, in order to optimize the dynamic performance of the notch filter, its phase angle is taken as the variable to be optimized. Taking the integral of the absolute value of time multiplies current as the objective function, the optimized design flow of the phase angle is given. The proposed optimized method does not rely on accurate mathematical model, and is more direct. Finally, the simulation and experiment results demonstrate the effectiveness of the optimal notch filter and also prove the system stability.

Microturbines at Drinking Water Tanks Fed by Gravity Pipelines: A Method and Excel Tool for Maximizing Annual Energy Generation Based on Historical Tank Outflow Data

Wherever the flow of water in a gravity pipeline is regulated by a pressure control valve, hydraulic energy in the form of water pressure can instead be converted into useful mechanical and electrical energy via a turbine. Two classes of potential turbine sites exist—those with (class 1, “buffered”) and those without (class 2, “non-buffered”) a storage tank that decouples inflow from outflow, allowing the inflow regime to be modified to better suit turbine operation. A new method and Excel tool (freely downloadable, at no cost) were developed for determining the optimal hydraulic parameters of a turbine at class 1 sites that maximize annual energy generation. The method assumes a single microturbine with a narrow operating range and determines the optimal design flow rate based on the characteristic site curve and a historical time series of outflow data from the tank, simulating tank operation with a numerical model as it creates a new inflow regime. While no direct alternative methods could be found in the scientific literature or on the internet, three hypothetically applicable methods were gleaned from the German guidelines (published by the German Technical and Scientific Association for Gas and Water (DVGW)) and used as a basis of comparison. The tool and alternative methods were tested for nine sites in Germany.

Design Optimization of V-sector Ball Valve Core

In order to solve the problem that the percentage characteristic of V-sector ball valve is poor at the relatively small opening degree, a design optimization flow of valve core is proposed for the first time. The process uses numerical simulation, sample mean evaluation and area average equivalence to calculate the equal percentage characteristics coefficient RQ of DN65 V-sector ball valve core, and uses experiments to verify the rationality of the process, and further extends it to other models of ball valves. The results show that the original DN65 V-sector Ball valve core does not meet the equal percentage characteristics in the opening area of 28.6 % to 7.1 %. After the optimized design, the equal percentage characteristics coefficient RQ of the ball valve core has been effectively improved, and the level of increase has more than doubled. And the equal percentage characteristics coefficient obtained by test exceeds the optimized design results. Further extended in the DN100 V-sector ball valve core, it is known that this optimization design method has universal applicability; V-sector ball valve core design optimization method is an efficient and reliable valve core design method, can improve the level of Valve core flow control, improve the valve core design ability.

Substrate integrated non-radiative dielectric waveguide and its applications

In this article a Substrate Integrated Non Radiative Dielectric Guide (SINRD) has been realized with the concept of substrate integration circuits. In SINRD, a specific pattern of air holes have been used grooved in a dielectric substrate to reduce the effective dielectric constant of a particular region. Accordingly, design and implementation of SINRD guides and its applications in millimeter wave subsystems have been investigated by using published literatures. Thereby the concept has been utilized to develop an optimized design flow of SINRD transmission line. Design has been carried out at W band (85–110 GHz) on a high dielectric constant substrate and subsequently dispersion characteristics has been studied subject to transmitted and radiated field configuration.

Design Implementation With Noninteger Multiple-Height Cells for Improved Design Quality in Advanced Nodes

Standard-cell libraries can be developed with different cell heights (e.g., in FinFET technology, corresponding to different numbers of fins). Larger cell heights provide higher drive strengths, but at the cost of larger area and power consumption as well as pin capacitance. Cells with smaller heights are relatively smaller in area, but have weaker drive strengths and are more likely to suffer from routing congestion and pin accessibility issues. Existing design methodologies and tool flows are able to mix cells with different heights at the block level (i.e., each block contains cells with heights being integer multiples of a particular “single row” cell height). To our knowledge, no design methodology in the literature or in production mixes cells with different, noninteger multiple heights in a fine-grained manner. In this paper, we propose a novel physical design optimization flow to implement design blocks with mixed cell heights in a fine-grained manner. Our optimization resolves the “chicken-and-egg” loop between floorplan site definition and the optimized choices of cell heights after placement with full comprehension of the constraints and costs of mixing cells of different heights (e.g., the “breaker cell” area overheads of row alignment between sub-blocks of 8 T and 12 T cell rows), our optimization achieves up to over 30% area and power reductions versus 12 T-only implementation while maintaining the same performance, and up to over 10% performance improvement along with power and area reductions versus 8 T-only implementation.

Multiphysics optimization design flow with improved submodels for salient switched reluctance machines

Multiphysics optimization design flow with improved submodels for salient switched reluctance machines

Traffic safety as a factor of improving logistics in construction sector

Security is a complex problem. It includes the driver’s behavior, the features of the vehicle, those of the road and the driving conditions. Security can be approached from the aspect of the vehicle and pavement design, of driving habits, traffic regulation and application of laws. The good coordination of the driver, the vehicle and the road enables for better estimation of the traffic safety relations and interrelations giving the possibilities of improvement of the situation at present and in future. The driver has the main role in the determination of the success or failure of the road system. Over 90% of the accidents are due to improper behavior of people in traffic. Understanding of the human factors is the key factor in the optimal road design and traffic flow. Nevertheless, engineers need more understanding about driving behavior, as they are responsible for road design, for the traffic flow, and for the regulations intended to avoid errors wherever possible. The purpose of this paper is to inform about the current situation both in practice and in the researches of traffic safety, as well as to yield a broader review of the actual traffic safety situation on the roads in Republic of Macedonia.

소방전원계통의 최적화 알고리즘 개발에 관한 연구

소방전원계통의 설계시에는 반드시 비상상태를 기준으로 계통의 용량과 전압강하의 영향을 고려하여야 한다. 비상상태를 고려하지 않은 소방전원계통의 설계는 비상상태 시, 전원용량의 미달과 전압강하의 영향으로 소방전기설비가 작동이 되지 않는 심각한 결과를 초례할 수 있다. 이에 본 논문에서는 실제 준공된 소방대상물을 대상으로, 전원공급장치의 용량 및 간선의 전압강하를 이론적으로 계산하여 문제점을 도출하고, 이를 해결하기 위해 선형회귀분석법을 이용한 전원공급장치의 최적 공급전압 산출 알고리즘과, 부하중심점을 고려한 최적 분산배치 알고리즘을 개발하여, 소방전원계통의 최적설계 Flowchart에 의한, 소방용 전원의 최적화 방안을 제안하였다. 그리고 제안된 최적화 방안을 문제점을 분석한 소방전원계통에 적용하여 시뮬레이션을 수행한 결과, 규정전압을 유지하면서 전원계통이 안정적으로 운용됨을 확인하였다. In designing an electric power system for fire protection, special consideration should be given to the effects of shortage of power capacity and voltage drop in preparation for emergencies. If fire protection design is ever made without considering emergencies, it can cause serious results by improper operation of fire protection systems in case of emergencies, especially due to the shortage of power capacity and main power line voltage drop. As such, this study carries out theoretical calculations of power capacities and main power line voltage drops of actual buildings which are being protected by fire protection systems, finds out the resultant problems, develops optimal algorithms for power supply calculation of electric power system by using a linear regression analysis and optimal algorithms for distributed arrangement considering a load center, and proposes an optimal method for electric power source for fire protection, which is based on optimal design flow charts in electric power system for fire protection. As a result of performing simulations, applying the proposed optimization method to electric power system for fire protection for which problem analysis has been made, it is found that the electric power system operates safely and properly, maintaining the rated voltage.

A New Application of Flow Duration Curve (FDC) in Designing Run-of-River Power Plants

The present study evaluates the effects of river run-off regime and hydrological uncertainty on the hydroelectric production of a run-of-river power plant. The mean annual energy from a plant was modeled as a function of run-off regime and design flow, by means of a procedure developed on the mean annual Flow Duration Curves (FDCs) of 15 sample basins in the Umbria Region (Central Italy). Results show that energy output decreases from constant to torrential regimes, following a potential function, and that, the greater the design flow, the greater the rate of decrease. The treatment and validation of these results provided a useful tool for easy identification of optimal design flow, according to the hydrological features of the basin and the target hydroelectric production at the station. Analyses of FDCs with a 20-year return period also showed that the decrease in energy production in dry years and its increase in wet years, compared with the mean annual value, are linearly linked to the design flow. In the present context of possible climate change, this result is presented as the possibility of partially controlling the effects of positive or negative flow rate trends. The results reported here can be applied to any kind of river and hydraulic technology at the power station.