Design and Fabrication of Cost-Effective Low-Speed Subsonic Open Type Wind Tunnel

Design and construction of an open loop subsonic high temperature wind tunnel for investigation of SCR dosing systems

In this study, the design of a wind tunnel was carried out to observe airflow through an airfoil, streamlines and turbine blades. To accommodate this, in this study a design was made of an open return wind tunnel. In this case, an open circuit wind tunnel type will be made because the construction is simpler and the manufacturing costs are relatively cheaper compared to the closed circuit wind tunnel type. The Wind Tunnel is designed with Open CLosed Wind Tunnel (OCWT) type. The OCWT is designed to consist of fan and housing, diffuser, test section, contraction, honeycomb. The OCWT design uses an operating fan to circulate air into the test section. The maximum air speed in the Test Section is 5 m/s with a flow that is closed to laminar. The recommended diffuser has a dimension of 50 cm on the side that is attached to the test section and 52 cm on the side facing the fan with an inclination angle of 1.79o. The driver uses a 16 inch exhaust fan with a power of 74 W to make the flow in the Test Section stable at a speed of 2 m/s.

Generally, the experimental aerodynamics is related to wind tunnel experiments. The wind tunnel design topic is very old but the development in computational fluid dynamics led to improvement in the wind tunnel design. This paper describes the design and optimization of low speed wind tunnel using CFD techniques. The new optimum wind tunnel will replace the old one featuring poor air quality and small area with lower wind speed at the test section. A computational domain was generated and adopted using ANSYS mesh generator and the solution domain was analysed by simulation technique using FLUENT CFD code in ANSYS Workbench package. The pressure drop calculations comparison between analytical, computational and experimental is included for different sections in the wind tunnel. The contraction cone was optimized using the response surface technique. The results identified that the pressure drop and turbulence level are modified as compared to the old wind tunnel.

The wind tunnel is proper functioning platform for accurate aerodynamic research which helps to provides adequate environment condition around scaled model to the compatible dimension. Wind tunnel data is part of design process that used to design their model. For correcting wind tunnel data of wall and mounting effects very careful techniques are used. But it shows limitation for linear flow approximation. This research paper proposed first part of the project i.e. design calculation and simulation i.e. flow in wind tunnel and checking incompressible flow in test section over an airfoil using CFD software. Test section design in rectangular shape for proposed wind tunnel. Contraction cone has contraction ratios 7 and cross section in rectangular shape. Diffuser design in conical shape with 5° diffusion angle and area ratio 1.33. The design philosophy is discussed along method for wind tunnel calculation is outlined. Using Computational fluid dynamics (CFD), design and simulation of flow parameter are investigated with systematic way in open loop wind tunnel. It shows good quality flow in test section as well as in entire wind tunnel. The proposed wind tunnel is conformed to design and can be used for different test in the field of aerodynamics. Wind tunnel design to achieve 40 m/s speed of air with expected low intensity turbulence level. Analysis of airfoil shows that good flow quality in test section. Lift and drag coefficient plotted against angle of attack.

On the basis of the overall structure design and aerodynamic calculation of the annular low-speed wind tunnel, this paper uses the CFD numerical simulation technique to study the influence of the contraction curve form, the contraction ratio and the open/closed loop form of the test section on the flow field quality of the wind tunnel test section, and then gives the three-dimensional geometric model and the numerical simulation results. It is found that the best flow field quality can be obtained by using the bicubic curve, the contraction ratio of 10.24 and the closed loop form of the test section under the same fan condition. The three-dimensional modeling method is adopted in this paper, which can obtain more accurate numerical simulation result than the two-dimensional modeling method. Thus, the numerical simulation result provides a solid theoretical basis for the design and construction of the actual low-speed wind tunnel.

A multipurpose subsonic wind tunnel facility has been designed for the Korea Air Force Academy in South Korea, and construction of this facility is nearing completion. This wind tunnel will be used in development of aircraft and ground vehicles as well as for basic studies in aeronautical engineering. The facility includes the wind tunnel and a building complex with offices, workshops, and test hall. The main test section dimensions are 2.45 m high, 3.5 m wide and 8.7 m long. Velocity ranges from 5 to 92 m/s with a fan power of 2,000 kW. High flow quality is achieved, with turbulence intensity designed to be below 0.05%rms (u'/U) and 0.1%rms (v'/U, w'/U). How angularity is designed to be less than +.0.1 deg. The wind tunnel has interchangeable test sections, several model support systems, a variety of instrumentation systems, and a probe traverse system. The external balance can be elevated to provide high accuracy for the various model types and to accommodate model/test section exchanges. The test facility systems and the building are integrated to provide excellent model handling and testing productivity. *Cheong-Ju, South Korea t Tullahoma, Tennessee 37388 Copyright * 1998 by Sverdrup Technology, Inc. Published by American Institute of Aeronautics and Astronautics, Inc., with permission. INTRODUCTION The government of the Republic of Korea and Korean industry are committed to establishing the capability for future aircraft development in Korea. The scope of this capability includes both military and civil systems. To meet this commitment, wind tunnels of sufficient size and capability are required. Several projects are now underway to support this effort. One of them, a subsonic wind tunnel undertaken by the Republic of Korea Air Force Academy (KAFA), is the subject of this paper. KAFA selected Sverdrup Technology, Lie. as the turnkey supplier of the subsonic wind tunnel, including preliminary and final design and construction services. Final design work has been completed and is covered in the present paper. Construction/installation and commissioning/calibration phases will be completed in 1998, and the results of that work will be presented in a future paper. FACILITY REQUIREMENTS During initial facility planning studies, KAFA configured the Subsonic Wind Tunnel as a closedcircuittype with interchangeable, atmospheric-pressure test sections. To support the Republic of Korea's commitment to aircraft and ground vehicle systems, the main testing activities planned to be conducted in the facility are: • Configuration optimization of aircraft • Development of high hit devices • Wing/body integration American Institute of Aeronautics and Astronautics Copyright© 1997, American Institute of Aeronautics and Astronautics, Inc. • Ground passenger vehicle aerodynamics • Building aerodynamics • Full aircraft component integration • Rotor aerodynamics • Helicopter aerodynamics Facility design requirements were established based on these testing activities. The requirements for test-type, test section size, performance, and flow quality are summarized in Tables 1 and 2. Compared to other mediumand large-size subsonic facilities, the KAFA facility's performance and flow quality requirements are state-of-the-art, and they are appropriate for advanced experimental education programs and aircraft development programs.

The wind tunnel is an arrangement to simulate real aerodynamic parameters. An open circuit wind tunnel does not circulate the same fluid as working fluid rather uses environmental fluid circulated by a fan. This research paper documents the design, construction, and setup of a low-speed subsonic open wind tunnel at the National Innovation Center, Kirtipur. This wind tunnel produces a controlled stream of air to test the aerodynamic properties of objects or fluids. The wind tunnel developed at NIC is used for a variety of research activities related to the aerodynamics of different bodies such as testing of lift coefficient, drag coefficient, and pressure difference calculations on drones and rockets along with flow visualization in civil works signature bridges and high-rise buildings. Designed to be a general-purpose wind tunnel, it is the biggest of its kind in Nepal.

The design and fabrication of a low-speed wind tunnel (LSWT), which is a critical component for testing and comprehending aircraft aerodynamics, is presented in this study. Despite the increasing prominence of computational fluid dynamics (CFDs) in manufacturing engineering, wind tunnels remain essential for the intricate development of aircraft and automobile designs with complex flow interactions. Using SolidWorks, we focused on controlling flow turbulence approaching the test section, emphasizing performance and quality parameters. The construction of the wind tunnel used plywood with an axial fan regulating the airspeed, and Arduino facilitated data acquisition. The drag and lift on the Y Clerk Airfoil were quantified by two load cells along the XY-axis, complemented by a Pitot Static Tube and a multitube inclined plane manometer for pressure and velocity calculation. Fusion 360 simulation software was used to analyze pressure and velocity profiles at speeds ranging from 10 to 20 m/s, providing a comprehensive quantitative evaluation of the wind tunnel’s capabilities. By emphasizing both design innovation and quantitative performance metrics, this study underscores the continuing significance of wind tunnels in engineering.

Turbulence is important to be assessed in the design of wind tunnels. Undesired turbulence levels undermine the quality of fluid flow and accordingly the quality of scientific data. At the test section, the level of turbulence is critical. The amount of turbulence present in the test section of a subsonic wind tunnel has not been investigated in earlier researches. In the present research, a subsonic open-section wind tunnel installed at the authors’ facility is used as a testbed for turbulence investigation. Computational Fluid Dynamics that solves Reynolds Averaged Navier Stokes equations (RANS) is used as the scientific method for calculating the turbulent flow parameters. RANS instead of Large Eddy Simulation or Direct Numerical Simulation is adopted as a first step to identify large-scale eddies. The characterization of turbulence is performed though decomposition of fluctuating velocity components (u and v) in two-dimension.

Wind tunnel is an element or experimental device that plays an important role in the development of aerodynamics. In general, there are two types of wind tunnels: open-loop wind tunnels and closed-loop wind tunnels. Furthermore, based on the flow velocity in the wind tunnel, the wind tunnel can also be categorized into several types: low-speed wind tunnel and high-speed wind tunnel, including sub-sonic and supersonic wind tunnels. In this study it is used a low-speed closed-loop wind tunnel type. The maximum atainable velocity of airflow in the wind tunnel is about 46 m/s with turbulence intensity (TI) as low as 0.41 percent. The flow parameters that being evaluated in this study include the velocity profiles and intensity of turbulence (TI) in some parts or sections of the wind tunnel. Pressure measurements in the wind tunnel are performed using a Pitot tube connected to a calibrated pressure transducer. The measured values of pressures are then converted into the fluid velocities and turbulence intensities. The results show that the flow quality in the main test section of the wind tunnel is good enough. The intensity of the flow turbulence on the inlet side of the test section is about 0.41 percent at the centerline velocity of approximately 40 m/s. In some parts of the wind tunnel, turbulence intensity is still relatively high, as in the small elbow outlet where TI is higher than 18 percent.

In this paper, low-speed smoke wind tunnel has been designed and fabricated for the insects’ flow field visualization. The test section and the contraction section of the tunnel are optimized and determined as to size by the method of computational fluid dynamics. And fairing devices are equipped in different sections to reduce the turbulence intensity and increase the flow uniformity in the experimental sections. For the smoke visualization of small insects, the smokeemitting equipment has been specially designed and carefully debugged. Composed of wind tunnel, light source and high-speed camera, experimental platform for visualization and filming of insect flight flow field has been established. B esides, the feasible and stable method for insect fixing has been designed. With the smoke wind tunnel, flow filed visualization experiment for the honeybee’s flapping was conducted and smoke flow filed in the experiment was recorded and analyzed. Near-filed and far-filed vortex structure when the honeybee fly can be recorded clearly. The expe rimental results indicate that the experimental platform is appropriate for flow filed study on insects flapping. Keyw ords: wind tunnel; honeybee; smoke lines; flow field

The design of a new transonic wind tunnel to reproduce bypass aero-engine flow conditions is described. This study has been driven by the interest to investigate and optimize the aero-thermal effects of an air/oil integrated surface heat exchanger placed at the inner wall of the secondary duct of a turbofan. The test section of the intermittent wind tunnel consists of a complex three-dimensional (3D) geometry. The flow evolves over the splitter, duplicated at real scale, as it does in the engine, guided by helicoidally shaped lateral walls. Numerical flow analyses have been used to guide the design of the complete wind tunnel. Zero-dimensional models have been developed to recreate the wind tunnel behaviour. Two- and three-dimensional computations have been performed to optimize the test section and the inlet guide vanes that duplicate the flow downstream of the engine fan. The reproduction of the bypass flow structure has been numerically analysed. Flow computations with and without the presence of instrumentation in the test section have been contrasted. Additionally, the influence of an aerodynamic probe on the flow has been studied numerically. This study should lead to improvements in the thermal management of future aircraft power plants, particularly by taking benefit of the cold bypass air to refrigerate the lubrication oil, without penalizing the propulsive efficiency.

A wind tunnel with advanced capabilities will aid research efforts to understand the complex fluid structure interaction problems encountered in aerospace engineering, industrial aerodynamics and wind engineering applications since wind tunnels remain an integral component of the design process for wind sensitive structures. Whether dealing with the aerodynamics of aerospace, mechanical or civil engineering structures many issues remain to be fully resolved-including the role of non-stationary gust interactions, Reynolds number effects, and the significance of small-scale turbulence. Building the next generation of such wind tunnels will contribute to the understanding of these issues. A combination Aerodynamic/Atmospheric Boundary Layer (AABL) Wind and Gust Tunnel with a unique active gust generation capability has been developed for various applications at Iowa State University (ISU). This wind tunnel is primarily a closed-circuit tunnel that can be also operated in open-return mode. It is designed to accommodate two test sections (2.44m x 1.83m and 2.44m x 2.21m) with a maximum wind speed capability of 53 m/s. This paper describes the wind tunnel and its components and presents a comparison of the predicted and measured design parameters. It shows that the wind tunnel is capable of generating uniform flow with very low turbulence in the aerodynamic test section and produces gust magnitudes around 27% of the mean flow speed.

Wind tunnel (WT) is a device that artificially produces airflow relative to a stationary body and measures aerodynamic force and pressure distribution, simulating the actual conditions with an important aspect of accurately feigning¬ the full complexity of fluid flow. The aim of the present study is to design the three dimensional geometry of a small, open-circuit (also known as Eiffel Type), and subsonic (low speed) wind tunnel (WT) capable of demonstrating or acting as a vital tool in aero-mechanics research. The project and fabrication itself, poses as an onerous task with the cynosure/central theme being the delineation/depiction of wind tunnel components such as Test Section, contraction cone, diffuser, drive system and settling chamber.

The The Republic of Indonesia is rich in potential for renewable energy, including abundant wind energy. This study aims to design a subsonic open return wind tunnel for testing wind turbines at low airspeeds. The testing focus includes the evaluation of blade efficiency, bearing performance, and other aspects. Testing at low airspeeds (<5 m/s) is highly relevant to the wind conditions in Indonesia. The design process utilizes Computer Aided Design (CAD), while data collection and analysis are conducted through Computer Aided Engineering (CAE) simulations and theoretical calculations. The wind tunnel comprises components such as contraction, honeycomb, test section, diffuser, and support structure. Airflow over the turbine blades can be observed using smoke visualization in the test section. This research is expected to provide practical contributions to the development of low-speed wind turbines in Indonesia.