Load Rejection Tests and Their Dynamic Simulations With a 150 kW Class Microsteam Turbine

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Susumu Nakano ◽  
Kuniyoshi Tsubouchi ◽  
Hiroyuki Shiraiwa ◽  
Kazutaka Hayashi ◽  
Hiroyuki Yamada
Keyword(s):  
Dynamic Simulation ◽  
Rotational Speed ◽  
Delay Time ◽  
Simulation Method ◽  
Dynamic Simulations ◽  
Machine Reliability ◽  
Delay Times ◽  
Simulation Results ◽  
Generator Output ◽  
Good Agreement

A simulation method for load rejection with a 150 kW class radial inflow steam turbine system was proposed to determine over rotational speed at load rejection. Simulations were carried out for several parameters of valves which are operated in an emergency. In addition, load rejection tests were carried out to confirm the machine reliability and to obtain results for comparison with the simulation results. Simulation results show that operation delay times of the steam release and vacuum break valves greatly affect over rotational speed at load rejection. Load rejection tests were done for generator outputs from 69 kW to 113 kW. Maximum over rotational speed of 54,160 rpm was measured at the generator output of 113 kW. Over rotational speed calculated by the dynamic simulation has relatively good agreement with the result for the operation delay time of 0.21 s. If the operation delay time of the steam release valves are kept as 0.21 s at the load rejection for the rated load of 150 kW, the over rotational speed is suppressed within 55,200 rpm which is less than the allowed rotational speed of 56,100 rpm.

Load Rejection Tests and Their Dynamic Simulations With a 150 kW Class Microsteam Turbine

2012 ◽  
Author(s):  
Susumu Nakano ◽  
Kuniyoshi Tsubouchi ◽  
Hiroyuki Shiraiwa ◽  
Kazutaka Hayashi ◽  
Hiroyuki Yamada
Keyword(s):  
Dynamic Simulation ◽  
Rotational Speed ◽  
Delay Time ◽  
Simulation Method ◽  
Dynamic Simulations ◽  
Machine Reliability ◽  
Delay Times ◽  
Simulation Results ◽  
Generator Output ◽  
Good Agreement

Simulation method for load rejection with a 150 kW class radial inflow steam turbine system was proposed to determine over rotational speed at load rejection. Simulations were carried out for several parameters of valves which are operated in an emergency. And load rejection tests were carried out to confirm the machine reliability and to obtain results for comparison with the simulation results. Simulation results show that operation delay times of the steam release and vacuum break valves greatly affect over rotational speed at load rejection. Load rejection tests were done for generator outputs from 69 kW to 113 kW. Maximum over rotational speed of 54,160 rpm was measured at the generator output of 113 kW. Over rotational speed calculated by the dynamic simulation has relatively good agreement with the result for the operation delay time of 0.21 s. If the operation delay time of the steam release valves are kept as 0.21 s at the load rejection for the rated load of 150 kW, the over rotational speed is suppressed within 55,200 rpm which is less than the allowed rotational speed of 56,100 rpm.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused is on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed, that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Optimization of geometrical design of clinching tools in clinching process with extensible dies

2016 ◽  
Vol 231 (21) ◽  
pp. 3889-3897 ◽  
Author(s):  
Xiaolan Han ◽  
Shengdun Zhao ◽  
Chen Liu ◽  
Chao Chen ◽  
Fan Xu
Keyword(s):  
Experimental Design ◽  
Simulation Model ◽  
Simulation Method ◽  
Orthogonal Experimental Design ◽  
Optimal Parameters ◽  
Geometrical Design ◽  
Reasonable Range ◽  
Simulation Results ◽  
Sliding Distance ◽  
Good Agreement

Due to the importance of geometrical design of clinching tools, the clinching process with extensible dies was investigated numerically and experimentally to seek for optimal parameters of clinching tools in this study. The joining parameters, including punch corner radius, sliding distance, die depth and bottom thickness, were optimized using the orthogonal experimental design simulation method based on the evaluation of tensile strength. The simulation results were validated through an experimental setup testing on material aluminum alloy Al5052. The orthogonal experimental design simulation results showed reasonably good agreement with the experimental results. To further investigate the validation of the simulation model, the different bottom thicknesses within a reasonable range of value were studied. The results also indicated that the simulation model could be employed to predict the joint forming by the clinching process with extensible dies.

Development of Ink-Particle Flight Simulation for Continuous Inkjet Printer

2013 ◽  
Author(s):  
Masato Ikegawa ◽  
Eiji Ishii ◽  
Nobuhiro Harada ◽  
Tsuneaki Takagishi
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Electrostatic Force ◽  
Simulation Method ◽  
Flight Simulation ◽  
Analysis Software ◽  
Continuous Type ◽  
Inkjet Printers ◽  
Simulation Results ◽  
Good Agreement

An ink-particle flight simulation method for industrial, continuous-type inkjet printers was developed to clarify the factors that influence the print distortion. Print distortion is produced by aerodynamic and electric interference between the ink-particles flying from the nozzle onto the print-target. The necessary functions to do this, such as the calculation of electrostatic force in the electric field between the electrodes, the Coulomb’s force from other charged ink-particles, and the drag force in the inkjet stream for many flying ink-particles were added to a Lagrangian method in the fluid dynamic analysis software that was used for the simulation. The trajectories of the ink-particles flying from this nozzle onto the print target and the air-flow caused by them were calculated simultaneously in the simulation. The simulation results for the velocities and trajectories of the flying ink-particles were compared with the experimental ones using a high-speed camera. These simulation results were in good agreement with the experimental ones, and this helps to clarify the factors that influence the print distortion.

Simulation of sliver blending and evaluation of blending irregularity

2021 ◽  
pp. 004051752110288
Author(s):  
Qiaoli Cao ◽  
Lili Qian ◽  
Hao Li ◽  
Chongwen Yu
Keyword(s):  
Simulation Method ◽  
Research Results ◽  
Blended Yarn ◽  
Blending Process ◽  
Fiber Components ◽  
Simulation Results ◽  
Experiment And Simulation ◽  
Good Agreement

The quality of blended yarn depends on the uniformity of the blending of the multi-component fibers in the yarn, and sliver blending is a process necessary for mixing fibers. The movement of fibers directly affects the distribution and mixing of fibers in the sliver. In this paper, the sliver blending process was simulated, and a method for the evaluation of sliver blending irregularity was proposed. The effects of passages of drawing and blending ratio on the sliver mixing uniformity were studied and verified both by experiment and simulation. The results show that the blending irregularity decreases gradually and tends to be stable with the increase of the passages of blending drawing. The more similar the blending ratio of the two components with approximately equal linear densities, the easier it is for the component fibers to mix evenly in the sliver. The simulation results are in good agreement with the measured values and previous research results. In addition, the blending irregularity of fiber components in the blended sliver can be predicted by the simulation method.

Dynamics Simulation of Automatic Rifle

2012 ◽  
Vol 482-484 ◽  
pp. 1547-1550
Author(s):  
Shan Lu ◽  
Bao Hua Wang ◽  
Ya Ping Qi
Keyword(s):  
Firing Rate ◽  
Dynamic Simulation ◽  
Simulation Method ◽  
Airway Device ◽  
Dynamics Simulation ◽  
Structure Parameters ◽  
High Firing Rate ◽  
Return Spring ◽  
Simulation Results ◽  
High Firing

By using dynamic simulation method, the launching technique of high firing rate for automatic rifle was studied. The influence of structure parameters of airway device, the stiffness of buffer spring and return spring on firing rate was studied. The simulation results provide the reference for the designing of high firing rate automatic rifle.

An Analysis on Dynamic Damage on Concrete Obstruct Subjected to Underwater Explosion Shock Waves

2006 ◽  
Vol 306-308 ◽  
pp. 1373-1378
Author(s):  
Li Hao ◽  
Jian Guo Ning
Keyword(s):  
Shock Waves ◽  
Underwater Explosion ◽  
Simulation Method ◽  
C Language ◽  
Damage Degree ◽  
Simulation Results ◽  
The Given ◽  
Dynamic Damage ◽  
Optimum Charge ◽  
Good Agreement

Based on the multi-material Eulerian algorithm, the damage effects of concrete obstruct subjected to underwater explosion shock waves are simulated by using the NM-MMIC code which is a 2D multi-material elastic-plastic hydrodynamics code with C++ language. According to the simulation results of underwater explosion, the optimum charge, the damage degree and the damage laws of obstruct are obtained. The simulation results show a good agreement with that obtained by DYNA2D. Thus the given study indicates that the model and algorithm presented in this paper are reasonable and the simulation method can be used for designing and estimating ammunitions against obstructs in water.

scholarly journals First-Principles Calculations of Shocked Fluid Helium in Partially Ionized Region

2012 ◽  
Vol 12 (4) ◽  
pp. 1121-1128 ◽  
Author(s):  
Cong Wang ◽  
Xian-Tu He ◽  
Ping Zhang
Keyword(s):  
Equation Of State ◽  
First Principles ◽  
Calculated Data ◽  
Molecular Dynamic Simulations ◽  
First Principles Calculations ◽  
Dynamic Simulations ◽  
Gas Gun ◽  
Atomic Ionization ◽  
Simulation Results ◽  
Good Agreement

AbstractQuantum molecular dynamic simulations have been employed to study the equation of state (EOS) of fluid helium under shock compressions. The principal Hugoniot is determined from EOS, where corrections from atomic ionization are added onto the calculated data. Our simulation results indicate that principal Hugoniot shows good agreement with gas gun and laser driven experiments, and maximum compression ratio of 5.16 is reached at 106 GPa.

scholarly journals Research on Simulation Method of Missile Adapter’s Separation Based on Combined Calculation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Miao Chen ◽  
Yi Jiang ◽  
Shaoyan Shi ◽  
Wei Zeng
Keyword(s):  
Grid Method ◽  
Simulation Method ◽  
Separation Process ◽  
Force Analysis ◽  
Wind Speeds ◽  
Force And Motion ◽  
Aerodynamic Parameters ◽  
Simulation Results ◽  
Container Type ◽  
Good Agreement

In the background of a container-type vertical launch missile, the simulation method of adapter separation in different wind speeds is researched. Based on force analysis of the adapters during their separation from the missile, the dynamic and kinematics equations of the adapter separation are established. The adapter’s aerodynamic parameters at different attitudes getting from the numerical wind tunnel are chosen to be the input. Through the dynamic simulation of the separation process of the adapters, the simulation results are in good agreement with the experimental data. The trajectory and placement distribution of adapters are obtained during the analysis of force and motion stance at different wind speeds. Then the relative distances between the adapter and missile or launch facility are determined. At the same time, it can be estimated that the combined calculation will save about two-thirds of time compared with dynamic grid method computing, which provides a significant guidance for the simulation method of adapter separation.

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