scholarly journals Analysis of Influence of Floating-Deck Height on Oil-Vapor Migration and Emission of Internal Floating-Roof Tank Based on Numerical Simulation and Wind-Tunnel Experiment

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1026
Author(s):  
Gao Zhang ◽  
Fengyu Huang ◽  
Weiqiu Huang ◽  
Zhongquan Zhu ◽  
Jie Fang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Loss Rate ◽  
Leeward Side ◽  
Design Management ◽  
Theoretical Support ◽  
Light Oil ◽  
Downwind Side ◽  
Gas Space ◽  
Space Volume

Internal floating-roof tanks (IFRTs) are widely used to store light oil and chemical products. However, if the annular-rim gap around the floating deck becomes wider due to abrasion and aging of the sealing arrangement, the static breathing loss from the rim gap will be correspondingly aggravated. To investigate the oil-vapor migration and emissions from an IFRT, the effects of varying both the floating-deck height and wind speed on the oil-vapor diffusion were analyzed by performing numerical simulations and wind-tunnel experiments. The results demonstrate that the gas space volume and the wind speed of an IFRT greatly influence the vapor-loss rate of the IFRT. The larger the gas space volume, the weaker the airflow exchange between the inside and outside of the tank, thereby facilitating oil-vapor accumulation in the gas space of the tank. Furthermore, the loss rate of the IFRT is positively correlated with wind speed. Meanwhile, negative pressures and the vortexes formed on the leeward side of the tank. In addition, the higher concentration areas were mainly on the three vents on the downwind side of the IFRT. The results can provide important theoretical support for the design, management, and improvement of IFRTs.

scholarly journals Wind Tunnel Test on Local Wind Field around the Bridge Tower of a Truss Girder

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Bing Huang ◽  
Yongle Li ◽  
Jiaxin Yu ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Field ◽  
Large Scale ◽  
Leeward Side ◽  
Local Wind ◽  
Height Range ◽  
Wind Barrier ◽  
Local Wind Field ◽  
Bridge Tower

The aerodynamic performance of vehicles on a bridge deck depends on the local wind field, especially in a region near a bridge tower. This study was carried out on a large-scale (1: 20.4) truss girder, and wind tunnel tests were performed to determine how the wind fields were affected by the bridge tower in the presence of different wind barriers. The wind barrier parameters significantly affect the wind field. Wind barriers should be sufficiently high to provide a wide protection range and have relatively small porosities to reduce the wind speed. The opening form of the wind barrier should also be considered, where a circular-holed form reduces the wind speed and turbulence more than a horizontal-slatted form. The wind field is affected by structures and bridge towers on the deck. A turning point in the wind speed occurs at a measurement point near the bridge tower, and this point gradually moves upward towards lanes on the leeward side of the bridge. The equivalent wind speed is significantly reduced over a four-meter height range because of shadowing from the bridge tower and the wind barrier.

Performance Test and Simulation Study on the Air Path of CAP1400 Passive Containment Cooling System

2017 ◽  
Author(s):  
Pan Xinxin ◽  
Huang Jingyu ◽  
Song Chunjing
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Air Flow ◽  
Wind Tunnel Test ◽  
Flow Path ◽  
Leeward Side ◽  
Wind Condition ◽  
Cfd Analysis ◽  
Test Results ◽  
Gradient Wind

As a large scale passive pressurized water reactor nuclear power plant, CAP1400 can remove the reactor decay heat to outside containment with the air cooling in the air flow path of passive containment cooling system (PCS) during the long-term period following an accident. Flow resistance characteristic and wind neutrality characteristic are the main performances of PCS air flow path. In order to study the performance of PCS air flow path, it is necessary to carry out the PCS wind tunnel test and computational fluid dynamics (CFD) analysis to establish a suitable method for the analysis of the performance of the air flow path. This paper comes up simulating the internal pressure and velocity distribution in the air flow path under different wind speed through CAP1400 PCS 1:100 scaled air flow path wind tunnel test to research the air flow resistance and internal flow pattern. The test shows that local uneven flow phenomenon exists in the outer annulus of the air flow path, but the wind pressure distribution of inner annulus is not affected by environment wind speed, wind direction angle, landforms and the surrounding buildings. The wind pressure is uniform at different heights on the cross section and shows the neutrality feature. Combining with CAP1400 PCS wind tunnel test, the CFD model is built. The measured inlet wind speed, turbulent kinetic energy and turbulent dissipation rate distribution parameters are inputs and the uniform wind conditions and gradient wind conditions of simulation analysis are developed. Simulation results show that: 1) In uniform wind condition, simulation result of pressure coefficient distribution trend at each cross section is consistent with the test trend and the deviation is very small, which basically can be controlled below 5%. The simulated differential pressures between inner annulus and outer annulus at different elevation are basically identical with the test results, which increase as the elevation arises. The simulated velocity distribution is basically identical with the test. The wind velocity at the upwind and central area of the flow path outlet is larger than other area, and a large swirling region comes on the leeward side near the wall 15cm, but simulated swirling region size at leeward side is slightly smaller. 2) In gradient wind condition, the pressure coefficient distribution trends are basically identical, and the deviation between the test and CFD analysis is 5–10% approximately. Considering the stability of gradient wind condition in wind tunnel is worse than that of uniform wind conditions, and more prone to wind speed fluctuations, therefore, the deviation is slightly greater than the uniform wind condition. According to the CFD simulation and wind tunnel test, it can be found that the simulation of air flow inside and outside annulus has a high precision though the test results are slightly affected by the instrument tubes along the two sides of test model. In general, CFD simulation and wind tunnel test results are basically identical. Therefore, CFD analysis method is well verified by PCS wind tunnel test, which can be applied to the analysis of the actual power plant.

scholarly journals EFFECTS OF TRANSVERSE AIR FLOW ON MASS LOSS RATE OF ALCOHOL POOL FIRES IN AN INCLINED WIND TUNNEL

2015 ◽  
Vol 21 (6) ◽  
pp. 798-803 ◽  
Author(s):  
Changfa Tao ◽  
Xishi Wang ◽  
Xiaonan Zhang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Burning Rate ◽  
Wind Direction ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Slope Angle ◽  
Edge Length ◽  
Pool Fires ◽  
Mass Burning Rate

In order to study the effects of inclined wind direction on combustion characteristics of alcohol pool fires, an inclinable wind tunnel was developed and used for providing venting wind with different directions. The wind tunnel can be sloped from 0° to 30° while the fuel pan is kept horizontal inside the tunnel. The wind speed can be altered from 0 to 3.0 m/s. The mass burning rate of square, rectangular and circular alcohol pool fires under different wind direction have been studied experimentally. The results show that the mass burning rate increases faster with increasing the slope angle of the wind tunnel and increasing the downstream edge length of the pool.

Extremely Gusty Winds from a Viewpoint of Aerodynamic Force

2020 ◽  
Author(s):  
Junji Maeda ◽  
Takashi Takeuchi ◽  
Eriko Tomokiyo ◽  
Yukio Tamura
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Rise Time ◽  
Aerodynamic Force ◽  
Step Function ◽  
Object Size ◽  
Aerodynamic Forces ◽  
Wind Force ◽  
Wind Observation

To quantitatively investigate a gusty wind from the viewpoint of aerodynamic forces, a wind tunnel that can control the rise time of a step-function-like gust was devised and utilized. When the non-dimensional rise time, which is calculated using the rise time of the gusty wind, the wind speed, and the size of an object, is less than a certain value, the wind force is greater than under the corresponding steady wind. Therefore, this wind force is called the “overshoot wind force” for objects the size of orbital vehicles in an actual wind observation. The finding of the overshoot wind force requires a condition of the wind speed recording specification and depends on the object size and the gusty wind speed.

scholarly journals 2.5D Flexible Wind Sensor Using Differential Plate Capacitors

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3101
Author(s):  
Yu Wan ◽  
Zhenxiang Yi
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Parallel Plate ◽  
Electrode Array ◽  
Copper Electrode ◽  
Windward Side ◽  
Leeward Side ◽  
Electrode Layer ◽  
Young’S Moduli ◽  
Speed Up

In this paper, a novel 2.5-dimensional (2.5D) flexible wind sensor is proposed based on four differential plate capacitors. This design consists of a windward pillar, two electrode layers, and a support layer, which are all made of polydimethylsiloxane (PDMS) with different Young’s moduli. A 2 mm × 2 mm copper electrode array is located on each electrode layer, forming four parallel plate capacitors as the sensitive elements. The wind in the xy-plane tilts the windward pillar, decreasing two capacitances on the windward side and increasing two capacitances on the leeward side. The wind in the z-axis depresses the windward pillar, resulting in an increase of all four capacitances. Experiments demonstrate that this sensor can measure the wind speed up to 23.9 m/s and the wind direction over the full 360° range of the xy-plane. The sensitivities of wind speed are close to 4 fF·m−1·s and 3 fF·m−1·s in the xy-plane and z-axis, respectively.

Study on the Relation Between Side Ratios of Rectangular Cross Sections and Secondary Vortices at Trailing Edge in Motion-Induced Vortex Excitation

2017 ◽  
Author(s):  
Kazutoshi Matsuda ◽  
Kusuo Kato ◽  
Kouki Arise ◽  
Hajime Ishii
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Cross Sections ◽  
Leading Edge ◽  
Trailing Edge ◽  
Wind Speeds ◽  
Smoke Flow ◽  
Flow Visualizations ◽  
Institute Of Technology ◽  
Secondary Vortices

According to the results of conventional wind tunnel tests on rectangular cross sections with side ratios of B/D = 2–8 (B: along-wind length (m), D: cross-wind length (m)), motion-induced vortex excitation was confirmed. The generation of motion-induced vortex excitation is considered to be caused by the unification of separated vortices from the leading edge and secondary vortices at the trailing edge [1]. Spring-supported test for B/D = 1.18 was conducted in a closed circuit wind tunnel (cross section: 1.8 m high×0.9 m wide) at Kyushu Institute of Technology. Vibrations were confirmed in the neighborhoods of reduced wind speeds Vr = V/fD = 2 and Vr = 8 (V: wind speed (m/s), f: natural frequency (Hz)). Because the reduced wind speed in motion-induced vortex excitation is calculated as Vr = 1.67×B/D = 1.67×1.18 = 2.0 [1], vibrations around Vr = 2 were considered to be motion-induced vortex excitation. According to the smoke flow visualization result for B/D = 1.18 which was carried out by the authors, no secondary vortices at the trailing edge were formed, although separated vortices from the leading edge were formed at the time of oscillation at the onset wind speed of motion-induced vortex excitation, where aerodynamic vibrations considered to be motion-induced vortex excitation were confirmed. It was suggested that motion-induced vortex excitation might possibly occur in the range of low wind speeds, even in the case of side ratios where secondary vortices at trailing edge were not confirmed. In this study, smoke flow visualizations were performed for ratios of B/D = 0.5–2.0 in order to find out the relation between side ratios of rectangular cross sections and secondary vortices at trailing edge in motion-induced vortex excitation. The smoke flow visualizations around the model during oscillating condition were conducted in a small-sized wind tunnel at Kyushu Institute of Technology. Experimental Reynolds number was Re = VD/v = 1.6×103. For the forced-oscillating amplitude η, the non-dimensional double amplitudes were set as 2η/D = 0.02–0.15. Spring-supported tests were also carried out in order to obtain the response characteristics of the models.

scholarly journals Design and installation of vibration testing system for spring mounted model of wing

2015 ◽  
Vol 18 (4) ◽  
pp. 179-187
Author(s):  
Anh Tien Tran ◽  
Nam Ngoc Linh Hoang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Theoretical Analysis ◽  
Testing System ◽  
Vibration System ◽  
Ultrasonic Sensors ◽  
Wing Model ◽  
Suitable Area ◽  
Naca 0015 ◽  
Theoretical Dynamics

This paper presents the design and installation of measuring vibration system in wind tunnel area 1m x 1m. The theoretical analysis of the spring structure in this model help we possible to design a system for wind tunnel by yourself with suitable area, wind speed as well as survey wing model to obtain results desire. This system helps us to observe the oscillation of wing survey by eyes, but to know exactly how wing fluctuates, also the pitching angle of wing, we use ultrasonic sensors to measure the distance variation, will be presented in more detail in the text. At the same time, the article also shows how to make a simple and durable wing model with NACA 0015 airfoil - wing model will be surveyed ranged in system above. The aerodynamic phenomena affect to the vibration of the wing are also mentioned and overcome in the design of the wing. Finally we process the data after measured to see the similarities between the experiment and the theoretical dynamics of aviation.

scholarly journals PENELITIAN MEKANISME STALL AKIBAT PERKEMBANGAN GELEMBUNG SEPARASI PADA SAYAP NACA 0017 SECARA EKSPERIMEN DI TEROWONGAN ANGIN SUBSONIK

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Agus Aribowo
Keyword(s):  
Reynolds Number ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Tunnel Experiment ◽  
Effect Mechanism ◽  
Subsonic Wind Tunnel

This paper presents the results of investigation the separation buble which growing and burst on aerofoil NACA 0017 with effect mechanism of stall in the subsonic wind tunnel. Experiment have done on wind speed 20 m per s and 30 m per s. The data pecked from the orifice of pressure with interval 2 degree until stall position. The result was separation buble which growing on the airfoil, going to ahead of airfoil together with increasing the Reynolds number. After touching, the flow appeared to separate from the upper airfoil without reattachment.

scholarly journals Numerical Simulation and Wind Tunnel Investigation on Static Characteristics of VAWT Rotor Starter with Lift-Drag Combined Structure

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6167
Author(s):  
Fang Feng ◽  
Guoqiang Tong ◽  
Yunfei Ma ◽  
Yan Li
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Speed Ratio ◽  
Static Characteristics ◽  
Torque Coefficient ◽  
Starting Characteristics ◽  
Static Torque

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.

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