bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical investigation of radial thrust fluctuation caused by diffuser rotating stall in a centrifugal pump
Authors: Takamine Taiki , Watanabe Satoshi 
Published: May 2022

Abstract
In this study, in order to understand the relation between the diffuser rotating stall and the fluctuating radial thrust, unsteady RANS simulation of a centrifugal pump was carried out. The rotating stall with single stall cell was qualitatively reproduced though the propagation speed was smaller than the experiment. The pressure amplitude caused by the rotating stall was comparable to the measured one, and the tendency that the propagation speed increases as the flow rate increases agreed with experiment. The radial thrust fluctuation due to the rotating stall was well evaluated by the simulation, and a considerable difference of phase angle between the stall cell position and the working direction of radial thrust was detected, which also agreed with experiment. On the basis of simulation result, the reason is found to be that the radial force acting on the impeller external wall at the liner ring section due to stall cell was not very small but comparable to that acting on the impeller blade and outer wall, while their working directions were roughly 100° different. This suggests that considering the leakage flow in numerical simulation is important to accurately predict the radial forces generated by rotating stall.
Mechanical property analysis of shaft tubular pump rotor with different blade angle based on fluid-structure interaction
Authors: Shen Jiawei , Pei Ji , Chen Songshan 
Published: May 2022

Abstract
Shaft tubular pump is widely used in large and medium-sized pumping stations with ultra-low head. But occasionally the blade cracks or even breaks, which seriously restricts the safe and stable operation of the pump station. In order to obtain the mechanical properties of the pump rotor with different blade installation angles, the fluid-structure interaction numerical simulation method is applied to analyze the structure of the pump rotor. Based on the SST k-ω model and the structured grid of the whole flow field, the three-dimensional numerical simulation of the internal flow field of the pump device is carried out by using CFX, and the reliability of the simulation is verified by model test. Then, the static analysis and modal analysis of the pump rotor structure under different working conditions are carried out by using Workbench. From the results, it can be found that the axial force increases with the increase of blade installation angle at a same flow rate. And at a same flow rate, the maximum deformation and equivalent stress increases with the increase of the blade installation angle. Finally, the change of the blade installation angle mainly affects the third and sixth order frequency which are only showed as blade vibration. Therefore, all of these results indicate that the blade installation angle has obvious influence on the mechanical property of the rotor of shaft tubular pump.
Numerical calculation and analysis of axial force of multistage centrifugal submersible pump
Authors: Dong Jian , Liang Wuke , Dong Wei 
Published: May 2022

Abstract
The study of axial force has been a hot spot in fluid mechanics research, and the magnitude of axial force directly affects the stability, safety, and efficiency of submersible pumps. This paper takes 200QJ50 multistage centrifugal submersible pump with spatial guide vane as the research object, simulates and numerically calculates the internal flow field of multistage submersible pump based on Standard k-ε turbulence model, a SIMPLE algorithm, and high-resolution format through CFX software, analyzes the distribution law of static pressure and velocity field of the multistage submersible pump under 0.7Qd
, 0.8Qd
, 0.9Qd
, 1.0Qd
and 1.1Qd
working conditions and compared the theoretical and simulated values of the corresponding axial force for each working condition. The results show that with the increase of the flow rate, the axial force of the multistage submersible pump shows a downward trend; the axial force generated by the first stage impeller has a larger proportion, and reaches the maximum value in the design condition; the traditional axial force calculation formula can more accurately predict the axial force under the design condition, and the error is 6%. The results of this study can provide references for the design and optimization of multistage centrifugal submersible pumps.
Multi-objective design optimization of industrial pump inducer to avoid cavitation instabilities
Authors: Masuda Itsuki , Takao Shunya , Nakamura Yushi , Miyabe Masahiro 
Published: May 2022

Abstract
In this paper, important four design parameters which are sweep radius, sweep angle, solidity and incidence angle were firstly extracted for the inducer shape optimization. A multi-objective optimization method was applied to the inducer and optimal design was manufactured by 3D-Printer. Pump performance tests and cavitation performance test were conducted for both baseline inducer and optimal one. In addition, internal flow at the inlet of the inducer was measured by PIV in order to investigate the onset and the scale of backflow. As the result, it was confirmed that the cavitation performance of the optimized inducer was improved by about 23% while maintaining pump efficiency. It was also clarified that the onset of backflow at partial flow rate was shifted to lower flow rate by PIV. Furthermore, the occurrence range of cavitation surge in the partial flow rate was narrowed. Based on the sensitivity analysis result, it was found that the influence of sweep radius on both cavitation performance and backflow onset was large. Moreover, some design guidelines are suggested in conclusion.
Investigation on the circumferential grooves effects in a two-stage axial flow compressor
Authors: Dou Xiangyuan , Wang Tong , Qu Xiaoyun 
Published: May 2022

Abstract
The performances of a two-stage industrial axial-flow compressor were tested to investigate the effects of circumferential grooves. The corresponding numerical models with four-blade cascade were set up. The numerical and test results showed that the operation range of the compressor near stall point can be extended obviously by the circumferential grooves. The internal flow field of the compressor was analysed numerically in detail, especially the tip leakage flow. It was found that stall occurred originally in the first stage and the local flow rate of the tip leakage was approximately proportional to the corresponding blade load. In addition, the local flow rate of tip leakage tended to decrease gradually along the flow direction near stall point. The tendency indicated that there were the most part of the blade load in the front of the rotor. It was proposed that the circumferential grooves could be set up at a specific stage in the multistage axial flow compressor where stall might occur originally to extend the operation range with lower manufacturing cost. Meanwhile, several circumferential grooves in the front segment of the rotor would be enough to play the effect on the stability enhancement for the axial compressor.
Effects of vortex generator on the performance of a flush-intake duct in oblique navigation
Authors: Huang C L , Chen L , Dai R 
Published: May 2022

Abstract
Effects of vortex generator (VG) on the flow field in a flush-intake duct for waterjet propulsion are investigated numerically under various navigation conditions. Flow’s Reynolds-averaged Navier-Stokes equations (RANS) are solved with the SST-Kω turbulence model. Four VG blades are installed at the ship bottom ahead of the intake entrance. The VG blade is rectangular shaped with a height of 0.1D, a length of 0.3D, and an angle of attack of 20°. Results show that under the forward moving condition, VG device effectively restrains the flow separation on the duct ramp side and improves the section uniformity at intake exit under low inflow velocity ratio (IVR) condition. The duct efficiency gets improved over a wide IVR range. Under the oblique moving condition, there is no separation region on the duct ramp side at low IVR, but significant vortex appears on the lip side. VG device does not introduce any obvious extra negative effects on the hydraulic performance.
A study of sediment erosion of runner seal of a Francis turbine
Authors: Yonezawa K , Watamura T 
Published: May 2022

Abstract
Suspended sediment particles included in working fluid of hydro turbines often cause erosion and reduce reliability and lifetime of the hydro turbine. It is important for understanding and suppressing erosion problems to understand characteristics of two-phase-flows of liquid and solid particles. In the present study, experimental and numerical studies were carried out to understand mechanisms of erosion in runner seal of a Francis turbine. The experiments were carried out using small-scale seal models. Flow patterns were visualized using coated mica flakes to understand entire flow patterns and a particle image velocimetry were also carried out to measure velocity field in a meridional cross-section. Accelerated erosion tests were also carried out and it was observed similar erosion distributions to that was observed in the actual hydro-turbine. Numerical flow simulations were also carried out to examine mechanisms of the erosion, contributions of each forces acting on the particles and appropriate parameters to capture characteristics of liquid-solid flows and erosion distribution, which were observed in experiments.
Design of a point absorber wave energy converter for an indian coast
Authors: Kumar Prashant , Singh Devesh , Paul Akshoy Ranjan , Samad Abdus 
Published: May 2022

Abstract
Ocean waves are considered as a potential unharnessed renewable resource being 800 times denser than wind. India has a wide coastal area of nearly 7500 km, providing a huge potential for harnessing ocean wave energy. The article aims to present the parametric optimization of a point absorber wave energy converter (PAWEC) for a location near Ennore port of India. Indian offshore condition such as significant wave height, period, and amplitude was reviewed for their minimum, maximum, and average values for several years. Hydrodynamic coefficients such as Froude-Krylov force, radiation damping, added mass, diffraction, excitation and response amplitude operator are optimized through geometric optimization of PAWEC’s float. In hydrodynamic response analysis, only heaving motion is considered and all motion is neglected for the study. Regular wave is only considered for this study. Output parameters such as structure velocity and structure response are studied for the mentioned geometry. Power-take-off (PTO) device is simulated for maximum efficiency and the float velocity response is observed. Monthly variation in the mean absorbed power and efficiency of Point absorber is calculated with respect to ocean power.
Investigation of inter-stage passive flow control for turbine performance improvement on regulated two-stage turbocharger
Authors: Zou Z , Yang M , Zhou S , Ding Z , Tian Y , Deng K 
Published: May 2022

Abstract
The flow field coupling effect between the HPT (high pressure turbine) and LPT (low pressure turbine) introduces a particular flow structure to the two-stage turbocharging system. Compared to the isolated turbines, the performance of these two connected turbines will inevitably be affected by each other. However, in the open state of the bypass valve, the influence of the bypass flow on this flow field coupling effect is still unknown. In this study, the inter-stage performance interaction of regulated two-stage turbocharger was investigated through the three-dimensional numerical method. With the bypass valve open, the influence of different positions of the bypass branch on the inter-stage coupling effects is investigated. The results manifest that the different positions of the bypass branch significantly change the performance of low pressure turbine and the flow interactions within the inter-stage. When the bypass branch is on the right, the LPT efficiency improves by approximately 2.2%. The detailed flow field analysis of the inter-stage pipe, volute and rotor is conducted to reveal the flow mechanism behind the inter-stage interactions. Based on this investigation, a new passive flow control scheme is proposed to ameliorate the swirling flow at the LPT inlet and improve the performance of LPT.
High durability variable geometry turbine for commercial vehicle turbochargers
Authors: Gupta B , Hoshi T , Yoshizawa H 
Published: May 2022

Abstract
Transportation sector constitutes a major portion in the Green House Gas (GHG) emissions of the world. Reduction of GHG emission requires the development of highly efficient Internal Combustion Engines (ICE) which are downsized using turbochargers that provide compressed air for cleaner combustion. Variable Geometry (VG) turbochargers are widely accepted for this application because of the ability of VG turbine to function at wider flow range. This ensures the supply of compressed air at low engine speeds also. However, the interaction between stator vanes and turbine rotor has been a major issue in terms of High Cycle Fatigue (HCF) of such a turbocharger. Till now, a conservative design approach constrained the maximum rotation speed to below resonance speed for vibration mode 2. But, to achieve further downsizing it would be necessary to challenge higher rotation speeds. This paper will firstly introduce the tip-timing experiment and CFD-FEA simulations used to evaluate the HCF of VG turbine, and secondly it discusses the results of new VG turbine system which achieved safe operability even at vibration mode 3, both on simulation and experiment. The tip-timing experiment was conducted at 680°C on hot gas stand test bench with optical sensors installed circumferentially around the rotor tip. These measurements have been verified and validated with the safety factor calculated from blade surface pressure data obtained from transient rotor CFD simulations.
Aerodynamic investigation on compact variable compressor for vehicular turbochargers
Authors: Yonemura Atsushi , Sakisaka Ryota , Kaneko Yudai , Morita Isao , Nagao Kenichi , Bamba Takahiro 
Published: May 2022

Abstract
In order to install a turbocharger which has wider operating range and higher boost pressure than a current supercharging system to an internal combustion engine (ICE) and a hybrid vehicle (HV), one development focus lies on a variable trim compressor (VTC) which can change passage area upstream a compressor wheel. In this paper, a new variable geometry device which was developed from the VTC mechanism proposed by Fujiwara et al. in 2018 is studied. The experimental result confirmed the performance enhancement associated with the design concept change and the improvement of trim actuation. In addition, the effect of the throat area ratio as design parameter in the new device on performance was numerically analysed. As a result, the optimal design value of passage area size in the VTC was around 60% and the passage area change position should be placed as close as possible to the compressor wheel.
Influence of nozzle clearance of VG turbocharger turbine on performance and internal flow
Authors: Asanaka Y , Nishimura R , Miyagwa K , Yoshida T , Ebisu M 
Published: May 2022

Abstract
To realize a sustainable society, it is necessary to reduce exhaust gas from automobiles and improve fuel efficiency. Turbochargers are useful for the purpose and especially variable geometry (VG) turbochargers are often installed because their nozzle blade angle can be optimally changed according to the rotational speed of the engine. To change the angle, it is needed to provide the nozzle clearance on both hub and shroud sides. In this study, CFD (Computational Flow Dynamics) calculations of a turbocharger turbine were conducted. The rotational speed of the turbine was set to 10,000 rpm. The diameter of the wheel blade is 60 mm and the height of the nozzle blade was 9.71 mm. The following were mainly investigated: the effect of the nozzle clearance position or blade angle on turbine performance, and the effect of leakage vortex from nozzle clearance on the downstream flow in the wheel domain. First, the steady-state CFD analysis on the nozzle and wheel domain was conducted. Four models of nozzle clearance were used: No Clearance (NC), Hub Clearance (HC), Shroud Clearance (SC), and Hub and Shroud Clearance (HSC). And four nozzle blade angles were used. With the Shroud Clearance model, the torque efficiency was worst with every nozzle blade angle. It was also found that the leakage flow rate from the nozzle clearance affects the loss increase in the wheel domain. Second, the unsteady-state CFD analysis on the full domain (casing + nozzle + wheel +diffuser) was conducted to investigate the leakage flow from nozzle clearance. The turbulence model was DES (Detached Eddy Simulation). Hub Clearance model and Shroud clearance model were used. The leakage vortex generated from nozzle clearance was found to flow into the wheel domain. With each nozzle model, the rotating directions of those vortexes were opposite. By the rothalpy loss investigation with the Hub Clearance model, it was confirmed that the portions of wheel domain where two leakage vortexes flow into showed larger losses than other portions. Those portions were located diagonally in two places, and they rotated in the opposite direction to the wheel rotation. On the other hand, with the Shroud Clearance model, the portions where the rothalpy loss was large were not shown regularly.
Simulation Study of Reliability Model and Optimization for Electrical Power System
Authors: Wu Qicai , Yuan Haibin 
Published: May 2022

Abstract
An architecture with multi-parallel and multi-standby system of aircraft electrical power system is proposed, simulation study is given. First the reliability model of parallel system is formulated, and total system reliability model is obtained. Parallel subsystem number and standby subsystems number are the two parameters of reliability model. In order to maximize the system MTBF and minimize the purchase cost of each subsystem, a novel redundancy optimization function is proposed. Simulation results are analyzed to study the impact of parameters on the system reliability. Redundancy number and configuration of typical aircraft power system is also discussed from the viewpoint of application practice. Simulation result shows that the architecture is flexible, with the options to increase or decrease subsystems of parallel or standby systems to satisfy reliability and capacity requirement.
Simulated Analysis of Liquid System for High-power Power Electronic Equipment
Authors: He Xunan , Kang YuanLi , Li Peng 
Published: May 2022

Abstract
Liquid cooling system mainly provides cooling to high-power power electronic equipment on civil aircraft. It is an important support that it can ensure the high-power power electronic equipment working normally. In this paper, the modeling and simulation of cooling system are carried out. And it mainly focuses on the liquid cooling plate of high-power power electronic equipment. First, three kinds of simulated conditions are confirmed, which are variable temperature of cooling liquid, variable heat load of power electronic equipment and variable flow of cooling liquid. Then according to three kinds of simulated conditions, the performance of cooling system is validated, which is benefit to the design of liquid cooling system and liquid cooling plate.
3D Simulation Design of Ideal City
Authors: Zeng Min 
Published: May 2022

Abstract
From static and single model display to dynamic and complex scenes such as 3d animation of real estate and hotel, 3D roaming, 3D virtual city and character animation, all of these can be realized by strong technical strength. This project uses 3D Max to complete the animation production of park landscape planning, venue greening, community greening and real estate landscape. Its effect is real, three-dimensional, vivid, traditional renderings can not be compared. At the same time, a unique modeling scheme is proposed. Then, with the help of AE and PR, the animation clips are combined into videos to comprehensively show the real estate through multiple angles, giving viewers an immersive feeling.
Proposal of a New Agent-based Model and Its Validation by Simulation
Authors: Li Zhaowei , Tanaka Kenji , Zhang Jing 
Published: May 2022

Abstract
Transportation services are diversifying as the demand for logistics services and truck transportation increases. However, the subcontracting hierarchy has produced social problems such as excessive driver labor, dissatisfaction of recipients, and deterioration of distribution efficiency. In this study, we focused on these problems and proposed, designed, implemented, and verified a point-to-point (P2P)-type logistics platform that reflects user preferences. A P2P logistics platform is defined as a decentralized platform in which delivery schedules are made only by interactions between truck and package agents without any human intervention. This platform is based on logistics agent modeling and sacrifice volume and negotiation, and its construction and simulation are described. In addition, as a case study, the model’s effectiveness for time-insensitive cargo, the case of truck entry and exit for time-sensitive cargo, and the actual delivery and truck supply convergence were verified.
On the Modeling and Multi-objective Optimization Design of Compact Planar Ultra-wideband Impedance Transformer
Authors: Yang Nan , Wang Dong , Wang Gang 
Published: May 2022

Abstract
A versatile scheme for design of planar ultra-wideband impedance transformer is proposed by using fragment-type structures (FTS) for modeling and MOEA/D-GO for optimization. To improve the optimization efficiency, non-uniform FTS cells are applied. To find the optimal planar FTS transformer, two objective functions characterizing the return loss and the insertion loss of the impedance transformer, respectively, are defined on a ultra-wide bandwidth. For demonstration, a 25-ohm to 50-ohm FTS impedance transformer is designed, which acquires reflection coefficient lower than -20 dB and extra insertion loss less than 0.27 dB in ultra-wide frequency band of 0.89-5.00 GHz.
A Task Planning Simulation Method Based On Hungarian Algorithm
Authors: Gong Xunan , Li Hongmei , Yang Xuesheng 
Published: May 2022

Abstract
As information technology continues to evolve, the need for accuracy and efficiency in task planning in computer simulation continues to strengthen. Task planning is a key part of computer-generated resource planning. To improve the effectiveness of task planning, this paper tries to design a task planning method. Firstly, a task planning model is designed by decomposing the requirements of the task according to the task capability of the platform, describing the resources quantitatively, and extracting the constraints and objective functions. Then the Hungarian algorithm is used to solve the problem. Finally, a typical case is used to test the proposed method, which verifies the correctness and feasibility of the method.