Numerical Simulation of Terminal Shock Oscillation in Over/Under Turbine-Based Combined-Cycle Inlet

2017 ◽  
Vol 0 (0) ◽  
Author(s):  
Jun Liu ◽  
Huacheng Yuan ◽  
Meng Yao ◽  
Ning Ge
Keyword(s):  
Numerical Simulation ◽  
Separation Bubble ◽  
Control Point ◽  
Simulation Method ◽  
Combined Cycle ◽  
Key Factors ◽  
Oscillation Phenomenon ◽  
Shock Oscillation ◽  
Main Factors ◽  
Unsteady Numerical Simulation

AbstractThe physical characteristics of self-sustain shock oscillation and the key factors that affect the shock oscillation in turbine-based combined-cycle(TBCC) inlet were investigated through unsteady numerical simulation method in this paper. The terminal shock oscillation in the throat was caused by the separation bubble appeared in the lower wall of the turbojet flowpath. The angle of the splitter and the offset of the diffuser were the main factors which affect the characteristics of the shock oscillation. When the angle of the splitter increased from 0 deg to 12 deg, the frequency of terminal shock increased from 100Hz to 133Hz; while when it was greater than 18 deg the terminal shock oscillation phenomenon disappeared. Different offset of the turbojet diffuser affect the motion of terminal shock in the inlet. When the y-coordinate value of the control point (y

Numerical Research on the Floor Heave Control of Deep Roadway in Coal Mining

2012 ◽  
Vol 524-527 ◽  
pp. 446-449 ◽  
Author(s):  
Fu Kun Xiao ◽  
Chun Jie Zhang ◽  
Li Wei Gao ◽  
Yang Yang Yue
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Good Effect ◽  
Optimal Program ◽  
Anchor Cable ◽  
Geological Conditions ◽  
Floor Heave ◽  
Mine Roadway ◽  
Numerical Research ◽  
Main Factors

On the engineering background of coal mine roadway orbit, according to the destruction of its original roadway, the paper have analyzed the situation of the deformation in the roadway , using the method of numerical simulation. Besides, it also determined the stress distribution and the forces supporting of roadway in the deformation process. Geological conditions, support patterns and bad construction are considered as the main factors of roadway damage and new support method is given. Numerical simulation method is used to study mechanism about anchor rod, anchor cable and anchor mesh coupled with the surrounding, bottom corner anchor rod and grouting to determine the optimal program. The new program is applied to the practice field and monitored, indicating that the application has a very good effect.

The Numerical Simulation of Iced Conductor and Research of Influencing Factors

2015 ◽  
Vol 734 ◽  
pp. 748-752
Author(s):  
Le Gao ◽  
Ji Cai Hu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Influencing Factors ◽  
Turbulence Intensity ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Key Factors ◽  
Wind Tunnel Tests ◽  
Aerodynamic Parameters ◽  
Micro Topography

In order to study the influence of some key factors such as the turbulence intensity related to micro topography and the diameter of conductor to the aerodynamic characteristics of iced conductor , the model is built based on the characteristic of iced conductor with crescent type ,to simulate the aerodynamic parameters for it and compare with the wind tunnel tests .The results show that we can make supplement reference to the wind tunnel tests through the numerical simulation method. Besides , we adjust the model and make research for the influence of diameter of conductor. The aerodynamic parameters we get can provide some reference to the research of galloping conductor.

Numerical Simulation and Experimental Research on Rolling Process of Conical Ring with Inner Steps

2007 ◽  
Vol 26-28 ◽  
pp. 993-997
Author(s):  
Xing Hui Han ◽  
Lin Hua ◽  
Jian Lan
Keyword(s):  
Numerical Simulation ◽  
Experimental Method ◽  
Experimental Research ◽  
Design Method ◽  
Fem Simulation ◽  
Simulation Method ◽  
Rolling Process ◽  
Experimental Results ◽  
Ring Rolling ◽  
Main Factors

The Conical Ring with Inner Steps (CRIS) is a typical profile ring, which is hard to be formed by ring rolling. Less-profile-filling and shrinking-drawing are the two main defects formed in the rolling process. Through the study of the rolling formability of CRIS with different ratio of height to diameter with the combination of FEM simulation method and experimental method, the main factors that affect the CRIS rolling formability are determined. The CRIS forging is designed. And the FEM simulation and experimental results show that the design method is reasonable.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

Visualization of separation and reattachment in an incident shock-induced interaction

2021 ◽  
pp. 095441002098349
Author(s):  
Yun Jiao ◽  
Chengpeng Wang
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Shear Stress ◽  
Separation Bubble ◽  
Incident Shock ◽  
Incident Shock Wave ◽  
Bottom Wall ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Oil Flow

An experimental study is conducted on the qualitative visualization of the flow field in separation and reattachment flows induced by an incident shock interaction by several techniques including shear-sensitive liquid crystal coating (SSLCC), oil flow, schlieren, and numerical simulation. The incident shock wave is generated by a wedge in a Mach 2.7 duct flow, where the strength of the interaction is varied from weak to moderate by changing the angle of attack α of the wedge from 8° and 10° to 12°. The stagnation pressure upstream was set to approximately 607.9 kPa. The SSLCC technique was used to visualize the surface flow characteristics and analyze the surface shear stress fields induced by the initial incident shock wave over the bottom wall and sidewall experimentally which resolution is 3500 × 200 pixels, and the numerical simulation was also performed as the supplement for a clearer understanding to the flow field. As a result, surface shear stress over the bottom wall was visualized qualitatively by SSLCC images, and flow features such as separation/reattachment and the variations of position/size of separation bubble with wedge angle were successfully distinguished. Furthermore, analysis of shear stress trend over the bottom wall by a hue value curve indicated that the relative magnitude of shear stress increased significantly downstream of the separation bubble compared with that upstream. The variation trend of shear stress was consistent with the numerical simulation results, and the error of separation position was less than 2 mm. Finally, the three-dimensional schematic of incident shock-induced interaction has been achieved by qualitative summary by multiple techniques, including SSLCC, oil flow, schlieren, and numerical simulation.

A numerical simulation method for molten material behavior in nuclear reactors

2017 ◽  
Vol 322 ◽  
pp. 301-312 ◽  
Author(s):  
Susumu Yamashita ◽  
Takuya Ina ◽  
Yasuhiro Idomura ◽  
Hiroyuki Yoshida
Keyword(s):  
Numerical Simulation ◽  
Nuclear Reactors ◽  
Simulation Method ◽  
Material Behavior ◽  
Molten Material ◽  
Numerical Simulation Method

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

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