509 Numerical Study on Transient Flow Characteristics in the Start-up Process of a Rocket Nozzle

2010 ◽  
Vol 2010.63 (0) ◽  
pp. 175-176
Author(s):  
Toshiaki Setoguchi ◽  
Shigeru Matsuo ◽  
Tokitada Hashimoto ◽  
Junji Nagao ◽  
Heuy-Dong Kim
Keyword(s):  
Transient Flow ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Rocket Nozzle ◽  
Start Up

scholarly journals Numerical Study of Thermal and Flow Characteristics of Plate-Fin Heat Sink with Longitudinal Vortex Generator Installed on the Ground

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Yen-Tso Chang ◽  
Han-Ching Lin ◽  
Chi-Jui Huang ◽  
Go-Long Tsai ◽  
Jinn-Feng Jiang
Keyword(s):  
Heat Sink ◽  
Transient Flow ◽  
Numerical Study ◽  
Thermal Flux ◽  
Flow Characteristics ◽  
Vortex Generator ◽  
Attack Angle ◽  
Longitudinal Vortex ◽  
Coolant Fluid ◽  
Transverse Distance

This study applied the commercial software ANSYS CFD (FLUENT), for simulating the transient flow field and investigating the influence of each parameter of longitudinal vortex generators (LVGs) on the thermal flux of a plate-fin heat sink. Vortex generator was set in front of plate-fin heat sink and under the channel, which was in common-flow-down (CFD) and common-flow-up (CFU) conditions, which have the result of vortex generator of delta winglet pair (DWP). In this study the parameters were varied, such as the minimum transverse distance between winglet pair, the attack angle of the vortex generator, fins number, the fin height, and the distance between the vortex generator and plate-fin. The coolant fluid flew into the fin-to-fin channel and pushed the vortex from different geometry toward the bottom. This phenomenon took off the heat from the plate to enhance the heat transfer. The numerical results indicated that the LVGs located close to the plate-fin heat sink are zero with the attack angle being 30°, presenting optimal overall conditions.

Numerical Study on Transient Dynamics in a Centrifugal Pump Considering Clearance Flow

2018 ◽  
Author(s):  
Chen-Xing Jiang ◽  
Xi Wang ◽  
Na-Xin Kang ◽  
Xiang-Yuan Zhang ◽  
Zhi-Jun Shuai ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Transient Flow ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Structure Design ◽  
Hydraulic Loss ◽  
Flow State ◽  
Axial Forces ◽  
Clearance Flow

This paper investigates the transient flow characteristics and the forces on the impeller in a single-stage centrifugal pump considering the clearance flow. The finite volume method is employed to simulate the dynamics process. First, Numerical simulation is carried out in a commercial code CFX. The external performance characteristics, internal flow structure and pressure fluctuation in the two different models, with clearance and without clearance, are compared. It is found that the existence of the clearance flow can generate more vortex and hydraulic loss, which makes the flow state more complicated. Besides, the transient radial and axial forces on the impeller are analyzed. And an optimized model with modified chamber flow field is proposed, which can provide a theoretical foundation on the structure design of the centrifugal pump.

Numerical simulation of transient flow field in a mixed-flow pump during starting period

2018 ◽  
Vol 28 (4) ◽  
pp. 927-942 ◽  
Author(s):  
Wei Li ◽  
Yang Zhang ◽  
Weidong Shi ◽  
Leilei Ji ◽  
Yongfei Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Transient Flow ◽  
Rotation Speed ◽  
Flow Characteristics ◽  
Mixed Flow ◽  
Content Type ◽  
Start Up ◽  
Study Results ◽  
Flow Pump ◽  
Stable Stage

Purpose This paper aims to study the transient flow characteristics in a mixed-flow pump during the start-up period. Design/methodology/approach In this study, numerical calculation of the internal flow field in a mixed-flow pump using the sliding mesh method was carried out. The regulation of the pressure, streamline and the relative speed during the start-up period was analyzed. Findings The trend of the simulated head is consistent with the experimental results, and the calculated head is around 0.3 m higher than the experimental head when the rotation speed reached the stable stage, indicating that the numerical method for the start-up process simulation of the mixed-flow pump has a high accuracy. At the beginning, the velocity inside the impeller changes little along the radius direction and the flow rate increases slowly during the start-up process. As the rotation speed reached the stable stage, the flow inside the impeller became steady, the vortex reduced and transient effects disappeared gradually. Originality/value The study results have significant value for revealing the internal unsteady flow characteristics of the mixed-flow pump and providing the reference for the design optimization of the mixed-flow pump.

Numerical study of the start-up process in an optimized rocket nozzle

2008 ◽  
Vol 12 (6) ◽  
pp. 485-489 ◽  
Author(s):  
José Antonio Moríñigo ◽  
José Juan Salvá
Keyword(s):  
Numerical Study ◽  
Rocket Nozzle ◽  
Start Up

Study on the Flow Characteristics of Shengli Oilfield Super Heavy Oil

2017 ◽  
Vol 10 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Wang Shou-long ◽  
Li Ai-fen ◽  
Peng Rui-gang ◽  
Yu Miao ◽  
Fu Shuai-shi
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Heavy Oil ◽  
Flow Characteristics ◽  
Fluid Viscosity ◽  
Linear Flow ◽  
Start Up ◽  
Non Linear ◽  
Core Permeability ◽  
Velocity Pressure

Objective:The rheological properties of oil severely affect the determination of percolation theory, development program, production technology and oil-gathering and transferring process, especially for super heavy oil reservoirs. This paper illustrated the basic seepage morphology of super heavy oil in micro pores based on its rheological characteristics.Methods:The non-linear flow law and start-up pressure gradient of super heavy oil under irreducible water saturation at different temperatures were performed with different permeable sand packs. Meanwhile, the empirical formulas between start-up pressure gradient, the parameters describing the velocity-pressure drop curve and the ratio of gas permeability of a core to fluid viscosity were established.Results:The results demonstrate that temperature and core permeability have significant effect on the non-linear flow characteristics of super heavy oil. The relationship between start-up pressure gradient of oil, the parameters representing the velocity-pressure drop curve and the ratio of core permeability to fluid viscosity could be described as a power function.Conclusion:Above all, the quantitative description of the seepage law of super heavy oil reservoir was proposed in this paper, and finally the empirical diagram for determining the minimum and maximum start-up pressure of heavy oil with different viscosity in different permeable formations was obtained.

Numerical study of influence of casting speed on fluid flow characteristics in the four strand tundish

2021 ◽  
Author(s):  
Kridsanapong Boonpen ◽  
Pruet Kowitwarangkul ◽  
Patiparn Ninpetch ◽  
Nadnapang Phophichit ◽  
Piyapat Chuchuay ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Casting Speed ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Fluid Flow Characteristics

A NUMERICAL STUDY ON THE HEMODYNAMIC AND SHEAR STRESS OF DOUBLE ANEURYSM THROUGH S-SHAPED VESSEL

2015 ◽  
Vol 27 (04) ◽  
pp. 1550033 ◽  
Author(s):  
Mahdi Halabian ◽  
Alireza Karimi ◽  
Borhan Beigzadeh ◽  
Mahdi Navidbakhsh
Keyword(s):  
Blood Flow ◽  
Mechanical Behavior ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
The Body ◽  
Sweep Angle ◽  
Abdominal Aortic ◽  
Hemodynamic Characteristics ◽  
Refined Meshes

Abdominal aortic aneurysm (AAA) is a degenerative disease defined as the abnormal ballooning of the abdominal aorta (AA) wall which is usually caused by atherosclerosis. The aneurysm grows larger and eventually ruptures if it is not diagnosed and treated. Aneurysms occur mostly in the aorta, the main artery of the chest and abdomen. The aorta carries blood flow from the heart to all parts of the body, including the vital organs, the legs, and feet. The objective of the present study is to investigate the combined effects of aneurysm and curvature on flow characteristics in S-shaped bends with sweep angle of 90° at Reynolds number of 900. The fluid mechanics of blood flow in a curved artery with abnormal aortic is studied through a mathematical analysis and employing Cosmos flow simulation. Blood is modeled as an incompressible non-Newtonian fluid and the flow is assumed to be steady and laminar. Hemodynamic characteristics are analyzed. Grid independence is tested on three successively refined meshes. It is observed that the abrupt expansion induced by AAA results in an immensely disturbed regime. The results may have implications not only for understanding the mechanical behavior of the blood flow inside an aneurysm artery but also for investigating the mechanical behavior of the blood flow in different arterial diseases, such as atherosclerosis.

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