Analysis of Concentric Canister Wall Roughness Effect on Jet Flow Based on Fluid Dynamics

2012 ◽  
Vol 252 ◽  
pp. 3-8
Author(s):  
Yun Shan Bai ◽  
Yi Jiang ◽  
Dong Mo Zhou
Keyword(s):  
Flow Field ◽  
Influence Factor ◽  
Great Influence ◽  
Internal Flow ◽  
Rough Wall ◽  
Concentric Cylinder ◽  
Smooth Flow ◽  
Practical Engineering ◽  
Mesh Update ◽  
Main Factor

Adopting concentric canister launchers (CCL), high temperature and high pressure environment of CCL is unfavorable for the missile launch. In addition to the gap between internal canister and external canister, injecting water for cooling are the main factor of impact the canister flow field, CCL’s rough wall is also a very important influence factor. In this paper, under the two working conditions of rough wall and smooth wall, use dynamic layering manner of moving mesh update method to simulate concentric canister missile launch process. The results reveal that rough wall has a great influence for pressure of concentric canister internal flow field, but the least influence for temperature. In practical engineering applications, need smooth surface material for smooth flow field exhaust when manufacturing concentric cylinder, but the non-concentric canister manufacturing of missile cold-launch canister, retain the rough wall can increase the pressure of the missile launch, this is conducive to missile launch, and also saves manufacturing costs, reduces processing procedures.

scholarly journals Analysis of the Influence of Different Bionic Structures on the Noise Reduction Performance of the Centrifugal Pump

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Centrifugal Pump ◽  
Great Influence ◽  
Frequency Doubling ◽  
Sound Field ◽  
Internal Flow ◽  
Test System ◽  
Centrifugal Pumps ◽  
External Characteristics

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.

Digital Analysis of Hydraulic Cone Valve Turbulence Based on Fluent 3D Solver

2013 ◽  
Vol 385-386 ◽  
pp. 93-96
Author(s):  
Hong Ji ◽  
Wei Guo Zhu ◽  
Song Chen ◽  
Jing Zhao
Keyword(s):  
Flow Field ◽  
Great Influence ◽  
Internal Flow ◽  
Energy Utilization ◽  
Valve Seat ◽  
Taper Angle ◽  
Turbulent Characteristics ◽  
Hydraulic Hammer ◽  
Drive And Control ◽  
And Control

The hydraulic cone valve is an important basic component in Fluid drive and control technology. Characteristic of cone valve inner flow filed influences directly the valves performance. Especially when fluid flow in runner is turbulent, characteristics of flow field have great influence on the valves working performance.Main work of this paper is numerical calculation and simulation of cone valve inner runner flow field inside hydraulic hammer. First make a 3D modeling for cone valve using Pro/E, by fluent this paper analyses and discusses the distribution of hydraulic cone valve internal flow field including flow velocity field, pressure field and flow, etc when the cone valve core taper angle is 30°, the gap is 0.5 mm, and inlet velocity is different, analyses position and strength of the vortex, and finds out the main reason for energy consumption.The results of the study show that by the optimal design of the cone valve seat, the density degree of the flow and the size of the vortex is reduced, the energy loss is reduced, negative pressure zone also changes, the noise is reduced and the energy utilization is improved.

scholarly journals Numerical Investigation of Flow Field and Energy Loss in a Centrifugal Pump as Turbine

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jingze Li ◽  
Dongrong Meng ◽  
Xun Qiao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Energy Loss ◽  
Entropy Generation ◽  
Flow Separation ◽  
Guide Vane ◽  
Great Influence ◽  
Internal Flow ◽  
Asymmetric Structure ◽  
Centrifugal Pumps

Centrifugal pumps as turbine (PAT) are widely used in petrochemical and water conservancy industries. The research on the internal flow field and energy loss of PAT is of great significance to improve the performance and efficiency of PAT. In this paper, experimental and numerical simulation methods are used to study the energy loss and flow field. The results show that the numerical simulation method can accurately simulate the internal flow field of PAT. And the entropy generation theory is applied to visualize the internal energy loss of PAT through the comparison of total pressure loss and entropy generation. The highest energy loss among PAT components is the guide vane. The loss in the guide vane is mainly caused by the flow separation caused by the wake of the guide vane and the asymmetric structure of the volute. The losses in the impeller are mainly due to flow separation and wake. Besides, the unsteady simulation results show that rotor-stator interaction has a great influence on the gap between the impeller and the guide vane. The research results provide a reference for the design of the PAT. This study is beneficial to studying the dynamic and static interference and PAT vibration to improve the stability of the PAT.

Research on the Performance Influence of the Flow Metering in the Natural Gas Pipeline with the Remit Pipe

2011 ◽  
Vol 52-54 ◽  
pp. 1458-1463
Author(s):  
Yong Xue Zhang ◽  
Zhi Cheng Shi ◽  
Chang Liu ◽  
Chan Guo
Keyword(s):  
Natural Gas ◽  
Flow Field ◽  
Economic Benefit ◽  
Flow Measurement ◽  
Gas Flow ◽  
Internal Flow ◽  
Natural Gas Pipeline ◽  
Flow Metering ◽  
Full Development ◽  
Main Factor

The flow measurement of the natural gas directly influences the economic benefit, which includes development, operation, allotment and the utilization in the industry of the natural gas. Moreover the structure of the pipeline is the main factor for the accuracy of the flow metering. In this paper, the research on the internal flow field of various kinds of pipe structure with the remit pipe, which are the different inflows and whether equipped with the panel rectifier separately, is done with the method of the numerical simulation and the experiment. The conclusion shows that the desire length to recover the full development turbulence section in the downstream of the remit pipe is most in the pipe structure with the stagger inlet-outlet and no rectifier. While that in the pipe structure with the opposite inlet-outlet and with a rectifier reaches the least. It can be got that the most appropriate installation site of the flow meter and the design of the pipe structure of the natural gas from the research on the influence pattern of the gas flow field.

scholarly journals A study of droplet evaporation coupling model based on Eulerian method

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Y. Tang ◽  
J. Shang ◽  
Y. Zhan
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Great Influence ◽  
Wind Tunnel Test ◽  
Internal Flow ◽  
Coupling Model ◽  
One Dimensional ◽  
Model Based ◽  
Eulerian Method ◽  
Thermodynamic Coupling

Research on engine icing is a hot topic among the world. Different from the aircraft wing or airframe icing, the evaporation phenomenon in the internal flow field has a great influence on the engine icing. Moreover, the thermodynamic coupling between droplets and flow field is not available in current particle trajectory calculations, or only for one-dimensional situation. Therefore, a three-dimensional droplet trajectory calculation model based on Eulerian method is used to demonstrate the thermodynamic coupling between droplets and flow field. The model was verified by NRC small engine icing wind tunnel test data and the flow field evolution is obtained which cannot be obtained by the one-dimensional coupling model. In the meanwhile, the effects of different initial LWC, relative humidity and MVD on the internal flow evaporation were studied, and the trends of droplets and flow field affected by evaporation were obtained. The numerical method in this paper can provide guidance for the subsequent research on engine icing.

An investigation of some parameter effects on the internal flow characteristics in the main nozzle

2016 ◽  
Vol 87 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Yuzhen Jin ◽  
Jingyu Cui ◽  
Linhang Zhu ◽  
Peifeng Lin ◽  
Xudong Hu
Keyword(s):  
Flow Field ◽  
Textile Industry ◽  
Great Influence ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Air Pressure ◽  
Weft Yarn ◽  
Internal Diameter ◽  
Air Jet ◽  
Air Jet Loom

The air-jet loom is widely used in the textile industry and the main nozzle is one of its key components. In this paper, the influence of some parameters, including the input air pressure and the structure of nozzle core and its internal diameter, on the internal flow field of the main nozzle is analyzed. Then the optimized structure of the main nozzle is proposed from the perspective of fluid dynamics. In the present simulations, the realizable [Formula: see text] model is applied to model the internal flow field of the main nozzle. The results show that the velocity in the annular throat reaches supersonic. Moreover, the pressure at the end of the nozzle core is the lowest in the main nozzle. It is also shown that the input air pressure has little effect on the axis velocity in Zone B, but on the other hand, has a great influence on the near-wall velocity field and the axis velocity in Zone C. In addition, an optimized structure of the nozzle core is proposed in this paper. It is found that with the proposed structure, the velocity boundary layer near the wall of Zone B in the accelerating tube can be well improved, and rapid diffusion of airflow in this area can be avoided. These help increase the moving speed of the weft yarn. Last but not least, we also show that decreasing of the internal diameter of the nozzle core improves the axis velocity of the weft accelerating tube. However, it brings a stronger turbulence at the same time.

scholarly journals The Influence of the Blade Outlet Angle on the Flow Field and Pressure Pulsation in a Centrifugal Fan

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1422
Author(s):  
Hongchang Ding ◽  
Tao Chang ◽  
Fanyun Lin
Keyword(s):  
Flow Field ◽  
Pressure Fluctuations ◽  
Great Influence ◽  
Internal Flow ◽  
Turbulent Energy ◽  
Design Flow ◽  
Centrifugal Fan ◽  
Frequency Multiplication ◽  
Outlet Angle ◽  
Blade Frequency

This paper takes centrifugal fan as the research object and establishes five impeller models with different blade outlet angles. By means of computational fluid dynamics (CFD), the external characteristics of the centrifugal fan and the internal characteristics, including the velocity, pressure, and turbulent energy distribution, at the middle span plane of the impeller or fan were obtained and compared. In addition, the pressure fluctuations surrounding the impeller outlet were also analyzed. The results showed that the change of the blade outlet angle of the centrifugal fan had a great influence on the performance; the total pressure and efficiency of the fan were the highest when the outlet angle of the blade was increased to 29.5° under the design flow rate; and the influence of the outlet angle on the fan performance was different in off-design conditions. On the other hand, at different flow rates, the change of the internal flow field with the increase of the outlet angle was different. For the pressure fluctuation of the fan, by increasing the blade outlet angle properly under high flow conditions, the fluctuation amplitude of the fan at the blade frequency and its frequency multiplication could be reduced, which is conducive to decreasing the impeller noise. The research results have good guiding significance regarding the design of the pneumatic performance and noise reduction performance of centrifugal fans.

THE INTERNAL FLOW FIELD ASSOCIATED WITH YAWED THREE-DIMENSIONAL RECTANGULAR CAVITIES

2000 ◽  
Vol 7 (3) ◽  
pp. 14
Author(s):  
Eric Savory ◽  
Norman Toy ◽  
Shiki Okamoto ◽  
Yoko Yamanishi
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Internal Flow

scholarly journals Influence of wall roughness on cavitation performance of centrifugal pump

2021 ◽  
Vol 43 (6) ◽  
Author(s):  
Weihui Xu ◽  
Xiaoke He ◽  
Xiao Hou ◽  
Zhihao Huang ◽  
Weishu Wang
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Internal Flow ◽  
Wall Roughness ◽  
Blade Surface ◽  
Centrifugal Pumps ◽  
Three Dimensional Model ◽  
Cavitation Inception ◽  
Cavitation Performance ◽  
Critical Cavitation

AbstractCavitation is a phenomenon that occurs easily during rotation of fluid machinery and can decrease the performance of a pump, thereby resulting in damage to flow passage components. To study the influence of wall roughness on the cavitation performance of a centrifugal pump, a three-dimensional model of internal flow field of a centrifugal pump was constructed and a numerical simulation of cavitation in the flow field was conducted with ANSYS CFX software based on the Reynolds normalization group k-epsilon turbulence model and Zwart cavitation model. The cavitation can be further divided into four stages: cavitation inception, cavitation development, critical cavitation, and fracture cavitation. Influencing laws of wall roughness of the blade surface on the cavitation performance of a centrifugal pump were analyzed. Research results demonstrate that in the design process of centrifugal pumps, decreasing the wall roughness appropriately during the cavitation development and critical cavitation is important to effectively improve the cavitation performance of pumps. Moreover, a number of nucleation sites on the blade surface increase with the increase in wall roughness, thereby expanding the low-pressure area of the blade. Research conclusions can provide theoretical references to improve cavitation performance and optimize the structural design of the pump.

Experimental investigation on the three-dimensional flow field from a meltblowing slot die

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 724-732
Author(s):  
Changchun Ji ◽  
Yudong Wang
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Great Influence ◽  
Distribution Characteristics ◽  
Air Velocity ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Airflow Distribution ◽  
Slot Die ◽  
Center Area

AbstractTo investigate the distribution characteristics of the three-dimensional flow field under the slot die, an online measurement of the airflow velocity was performed using a hot wire anemometer. The experimental results show that the air-slot end faces have a great influence on the airflow distribution in its vicinity. Compared with the air velocity in the center area, the velocity below the slot end face is much lower. The distribution characteristics of the three-dimensional flow field under the slot die would cause the fibers at different positions to bear inconsistent air force. The air velocity of the spinning centerline is higher than that around it, which is more conducive to fiber diameter attenuation. The violent fluctuation of the instantaneous velocity of the airflow could easily cause the meltblowing fiber to whip in the area close to the die.

Sign in / Sign up

Export Citation Format

Share Document