scholarly journals Numerical Simulation of Flow Field of DN2400 Hedge Dissipator

2018 ◽  
Vol 246 ◽  
pp. 01117
Author(s):  
Huipan Tan ◽  
Jianghe Sun ◽  
Zhifang Liao ◽  
Baiyun Zhang ◽  
Zherun Tang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Flow Field ◽  
Delivery System ◽  
Internal Flow ◽  
Stable Operation ◽  
Water Delivery ◽  
Long Distance ◽  
Water Separation ◽  
Energy Dissipator ◽  
Accident Conditions

The distribution of water resources in China is uneven. Long distance water conveyance projects have effectively solved this problem. In the water delivery system, the energy dissipator plays an important role in pressure regulation and regulation. Therefore, the design and structure of the energy dissipator affect the working efficiency and stable operation of the whole water delivery system, and it is of great significance to study the internal flow field of the energy dissipator. Based on a emergency project, this paper studies the internal flow field of the energy dissipation valve in A location and B location in the design conditions, accident conditions and water separation conditions to verify the DN2400 hedging energy dissipation. The rationality of the structural design of the device provides a reference for the design and improvement of the energy dissipator in the future.

scholarly journals Effects of Guide Vane Placement Angle on Hydraulic Characteristics of Flow Field and Optimal Design of Hydraulic Capsule Pipelines

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1378 ◽  
Author(s):  
Chunjin Zhang ◽  
Xihuan Sun ◽  
Yongye Li ◽  
Xueqin Zhang ◽  
Xuelan Zhang ◽  
...  
Keyword(s):  
Flow Field ◽  
Guide Vane ◽  
Fluid Structure Interaction ◽  
Internal Flow ◽  
Agricultural Products ◽  
Transport Cost ◽  
Hydraulic Characteristics ◽  
Long Distance ◽  
Fluid Structure ◽  
Structure Interaction

With the rapid growth of agricultural trade volumes, the transportation of agricultural products has received widespread attention from society. Aiming at these problems of low transport efficiency and high transport cost in long-distance transport of agricultural products, an energy-saving and environmental-friendly transport mode of agricultural machinery—hydraulic capsule pipelines (HCPs)—was proposed. HCPs effectively solve issues like traffic congestion, energy crises, and atmospheric pollution. Published literature is mainly limited to the capsule speed and the pressure drop characteristics of the fluid within the pipelines. This research was conducted on the following four aspects of HCPs. Firstly, the structure of the carrier was improved and called a ‘piped carriage’. Secondly, a coupled solution between the structural domain of the piped carriage and the fluid domain within the pipelines was numerically investigated by using the commercial CFD software ANSYS Fluent 12.0 based on the bidirectional fluid–structure interaction methods. Thirdly, the effects of guide vane placement angle on hydraulic characteristics of the internal flow field within the horizontal pipelines transporting the piped carriage were extensively evaluated. Finally, based on least-cost principle, an optimization model of HCPs was established. The results indicated that the simulated results were in good agreement with the experimental results, which further demonstrated that it was feasible to adopt the bidirectional fluid–structure interaction methods for solving the hydraulic characteristics of the internal flow field when the piped carriage was moving along the pipelines. This article will provide an abundant theoretical foundation for the rational design of HCPs and its popularization and application.

Study on Valve-Closure Water Hammer in Gravity Pressured Water-Delivery System with Branch Line

2013 ◽  
Vol 777 ◽  
pp. 341-346
Author(s):  
Ru Dong
Keyword(s):  
Delivery System ◽  
Water Hammer ◽  
Gravity Flow ◽  
Stable Operation ◽  
Valve Closure ◽  
Water Delivery ◽  
Security Measures ◽  
Pressurized Water ◽  
Branch Line ◽  
Practical Engineering

This paper analyzed the characteristics of valve-closure water hammer rising pressure, according to the basic theory of water hammer rising pressure in the gravity flow water-delivery system. It is indicated that the end valve-closure is the main cause of water hammer, and which is an important problem of influencing the safety and stable operation of the system. Combined With an engineering example that is a gravity pressurized water delivery system with the branch line, the paper studied water hammer rising pressure when the various combinations of valve-closure duration and angle . See that off valve water hammer boost of the branch line gravity flow system is more significant, more dangerous, so we recommend that reliable and effective security measures of practical engineering must be taken.

scholarly journals Experimental and Numerical Investigation of Pressure Fluctuation in a Low-Specific-Speed Centrifugal Pump with a Gap Drainage Impeller

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Li Zhang ◽  
Hui Li ◽  
Hong Xu ◽  
Weidong Shi ◽  
Yang Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Pulsation ◽  
Internal Flow ◽  
Stable Operation ◽  
Simulation Methods ◽  
Centrifugal Pumps ◽  
Numerical Simulation Methods ◽  
Low Specific Speed ◽  
Specific Speed

In order to analyze the effect of impeller with different slot widths on the performance of the low-specific-speed centrifugal pumps, based on the impeller of a single-stage pump with the specific speed of 21, two gap drainage schemes with slot widths of 1.5 mm and 6.0 mm, slot diameter of 180 mm, and lap length of 5 mm were designed. Both experimental and numerical simulation methods were applied to compare the steady performance, which includes the head, efficiency, and the internal flow field distribution, and the unsteady pressure pulsation performance between new designed pumps and the original pump. The results show that gap drainage would cause a certain degree of head reduction, but a smaller slot width could achieve higher efficiency. Meanwhile, a reasonable open seam scheme can reduce the development of pressure pulsation, which provides experience and reference for the stable operation of low-specific-speed centrifugal pumps.

Flow Measurement at Partial Flow Rate With LDV Around Rear Rotor of Contra-Rotating Axial Flow Pump

2007 ◽  
Author(s):  
Shuichi Yamashita ◽  
Satoshi Watanabe ◽  
Kusuo Okuma ◽  
Kyota Shirasawa ◽  
Akinori Furukawa
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Flow Measurement ◽  
Axial Flow ◽  
Internal Flow ◽  
Stable Operation ◽  
Pressure Measurements ◽  
Specific Speed ◽  
Axial Flow Pump ◽  
Flow Pump

An application of contra-rotating rotors, in which a rear rotor is employed in tandem with a front one and these rotors rotate in the opposite direction each other, has been proposed against a demand for developing higher specific speed axial flow pump. The internal flow field of pump should be considered in the design for higher performance and more stable operation. The flow field in contra-rotating axial flow pump was measured with LDV and wall pressure measurements. In the present paper, the experimental results are shown and the flow behaviors would be discussed.

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.

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.

scholarly journals Optimal Location of Energy Dissipation Box in Long Distance and High Drop Gravitational Water Supply System

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 461
Author(s):  
Weixiang Ni ◽  
Jian Zhang ◽  
Sheng Chen
Keyword(s):  
Energy Dissipation ◽  
Water Supply ◽  
Water Level ◽  
Pressure Head ◽  
Optimal Location ◽  
Water Supply Systems ◽  
Protective Effects ◽  
Long Distance ◽  
Optimal Position ◽  
Gravitational Flow

In the long-distance and high-drop gravitational water supply systems, the water level difference between the upstream and downstream is large. Thus, it is necessary to ensure energy dissipation and pressure head reduction to reduce the pipeline pressure head. The energy dissipation box is a new type of energy dissipation and pressure head reduction device, which is widely used in the gravitational flow transition systems. At present, there is still a dearth of systematic knowledge about the performance of energy dissipation boxes. In this paper, a relationship between the location of the energy dissipation box and the pressure head amplitude is established, a theoretical optimal location equation of the energy dissipation box is derived, and numerical simulations using an engineering example are carried out for verification. The protective effects of an energy dissipation box placed at the theoretical optimal location and an upstream location are compared. The results indicate that for the same valve action time, the optimal position allows effectively reducing the total volume of energy dissipation box. The oscillation amplitudes of the water level in the box and the pressure head behind the box are markedly reduced. Under the condition that the water level oscillation of the energy dissipation box is almost the same, the optimal location offers better pressure head reduction protection performance than the upstream location.

Visualization of Internal Flow Field of Propeller Fan

2017 ◽  
Author(s):  
Takaya Onishi ◽  
H. Sato ◽  
M. Hayakawa ◽  
Y. Kawata
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Laser Light ◽  
Internal Flow ◽  
Light Sheet ◽  
Tip Vortex ◽  
Laser Light Sheet ◽  
Blade Surface ◽  
Similar Tendency ◽  
Flow Phenomena

Propeller fans are required not only to have high performance but also to be extremely quiet. The internal flow field of ventilation propeller fans is even more complicated because they usually have a very peculiar configuration with protruding blades upstream. Thus, many kinds of internal vortices yield which cause noise and their cause and countermeasures are needed to be clarified. The purposes of this paper are to visualize the internal flow of the propeller fan from the static and rotating frame of reference. The internal flow visualization measured from the static frame gives approximately the scale of the tip vortex. The visualization from the rotating coordinate system yields a better understanding of the flow phenomena occurring at the specific blade. The experiment is implemented by using a small camera mounted on the shaft of the fan and rotated it to capture the behavior of the vortices using a laser light sheet to irradiate the blade surface. Hence, the flow field of the specific blade could be understood to some extent. The visualized results are compared with the CFD results and these results show a similar tendency about the generation point and developing process of the tip vortex. In addition, it is found that the noise measurement result is relevant to the effect of tip vortex from the visualization result.

Numerical Simulation of Flow in Imported Steam Turbine Inlet Components with Equilibrated Holes in High Performance

2013 ◽  
Vol 712-715 ◽  
pp. 1263-1267
Author(s):  
Shan Tu ◽  
Shu Ming Wu ◽  
Qi Zhou ◽  
Hong Mei Zhang ◽  
Xiao Qing Zhu
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
High Performance ◽  
Optimization Design ◽  
Great Influence ◽  
Control Valve ◽  
Stable Operation ◽  
Valve Seat ◽  
Valve Disc ◽  
Interior Flow

The main inlet component of steam turbine is control valve. The stable operation of the steam turbine control valve is vital for safe and stable operation of the steam turbine and safety production of the power plant. However, due to the complexity of the structure and unsteady characteristics of steam flow in the valve, there is not enough experimental method about the detailed flow characteristics of the area near control valve disc and the inside of the valve chamber up to now. This article is to focus on the simulation of the steam turbine control valve interior flow field which includes the valve pre-inlet channel in different conditions, then find the reasons which caused instability and pressure loss of the control valve by analyzing the flow field details, finally further optimization design. The profile matching of the valve disc and valve seat has a great influence on the interior flow field of control valve, so analysis of the high performance valve disc shape and divergence angle of valve seat is carried out, and the research conclusion is used for guide design and development of the control valve.

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