Introduction to Turning Vanes
Turning vanes – Unmatched Aerodynamic Solutions
In the realm of airflow management, the design of duct corners plays a key role in the efficiency and functionality of ventilation, HVAC systems, and wind tunnels. When air is forced to make a sharp turn, as is often required in ductwork, it encounters increased resistance, leading to higher pressure losses and the introduction of turbulence. This not only compromises the system’s efficiency by demanding more energy to maintain airflow but also impacts the structural integrity of the ductwork due to the uneven pressures exerted by turbulent flows. Additionally, these turbulent flows are a common source of noise, further detracting from the system’s overall performance and comfort provided to the end-users.
The traditional solution to this issue involves designing the corners as smooth radius-bends, which, while effective in reducing pressure losses and minimizing turbulence, come with their own set of challenges. The most significant of these is the increased space required to accommodate such bends. In large duct systems, implementing smooth radius-bends can lead to unreasonably large structures, making this approach impractical in many scenarios, especially where space is at a premium.
To improve aerodynamic efficiency, such a round bend is sometimes made with a smoothly curved splitter continuing along the entire duct bend, from the inlet to the outlet ductmate. This increases the material consumption, making it comparable to the material intensity of a duct elbow containing turning vanes. But the total weight and the airflow quality of the duct elbow with splitters are still worse than the turning vane solution.
This is where turning vanes, also known as corner vanes or guiding vanes, come into play. Designed to be installed within the corners, duct corner vanes allow the air to navigate the turn with minimal resistance, effectively reducing pressure losses and mitigating turbulence without the need for the additional space that smooth radius-bends demand. This makes turning vanes in duct elbows an ideal solution for managing airflow efficiently in a compact space.
TunnelTech‘s air distribution enhancement vanes are at the forefront of this technology, offering unparalleled efficiency in airflow management. Our products are designed for a wide range of applications, from indoor skydiving facilities and wind tunnels to HVAC turning vanes and ventilation systems, embodying the cutting-edge of aerodynamic design and energy efficiency.
Local Resistance, Efficiency and Design
TunnelTech’s high-performance airflow guides set the industry standard for power and aerodynamic efficiency. Our energy-saving duct turning vanes are engineered to minimize aerodynamic friction, ensuring smooth airflow and reducing energy consumption.
TunnelTech’s turning vanes have excellent airduct local resistance characteristics, calculated accurately using the well-known Darcy-Weisbach equation:
[math] \Delta P = \xi\cdot\rho\cdot\frac{v^2}{2} [/math]
Where: ΔP – total pressure losses (pressure drop) in Pa;
ξ – local resistance (Darcy-Weissbach) coefficient;
ρ – fluid density (kg/m3);
V – fluid velocity at the inlet cross-section (m/s).
TunnelTech’s turning vane Local resistance coefficient and corresponding pressure drop are presented in the corresponding figure above.
Please see the Airduct Corner Section Optimisation article to learn more about hydraulic resistance of air ducts and turning corner sections and related calculation methods.
Cooling and Heating Capability
Unique among guiding vanes for ducts, our products offer the capability to circulate coolant, allowing for efficient cooling or heating of the air as it passes through the duct. This feature opens up new possibilities for the use of indoor climate control vanes in thermal regulation, providing our clients with versatile solutions for their airflow needs.
Corner duct sections with cooled turning vanes can withdraw large amounts of heat, from hundreds of kilowatts to tens or even hundreds of megawatts.
In TunnelTech wind tunnels, the design heat dissipation at maximum power is typically in between 1 and 5 MW, depending on the model of the wind tunnel. However, if you need to use the cooled turning vanes in other installations, like large scale industrial air duct heat exchangers et.c, their heat dissipation will only be limited by the heat transfer surface area.
Since the vane profile and the area per 1 meter of vane length is constant, it is convenient to use a linear heat transfer coefficient HTCL for heat transfer calculations.
Knowing the operating mode of your equipment, you can determine the HTCL from the corresponding figure and calculate the required total length of all cooled turning vanes to dissipate the required power.
HTCL – Linear Heat Transfer Сoefficient (per meter of vane length) is given in the presented figure for both, dry (RH=0%) and humid air (RH=90% at 30 ˚C) at different coolant pressure difference (water) between inlet and outlet coolant channel ports.
Simply place an order in meters of turning vanes for ductwork you have!
Heat Transfer Coefficient parameters for the water-cooled turning vanes are given for TunnelTech’s standard port connection layout.
ΔP [kPa] in the figure above represents the water pressure difference between inlet and outlet vane ports (blue and red arrows on the scheme).
More details on the hydraulic loss coefficient, turning corner resistance and heat transfer coefficient are given in the Documentation section.
General parameters
| Standard ordering options | |
| Chord | 500 mm |
| Chord-to-Spacing ratio | ≥3:1 |
| Turning angle (standard) | 90˚ |
| Weight | 14.53 kg/m |
| Material | Aluminium |
| Surface treatment | Anodized |
Operating temperature range
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Custom ordering options | |
| Available vane length | 500 – 10000 mm |
Custom turning angle | 80˚ – 179˚ – custom vane angle 180˚ – symmetrical airfoil shape heat exchanger |
| Custom material | fiberglass |
Aerodynamic performance
Air duct local resistance * (Darcy – Weissbach factor, ξ) vs. air speed | 5 m/s – 0.048 20 m/s – 0.043 100 m/s – 0.031 |
Air duct pressure drop * (Pa) vs. air speed | 5 m/s – 0.7 Pa 20 m/s – 10.6 Pa 100 m/s – 191.6 Pa |
| Noise level | 60 … 75 dB – in the turning corner duct. 51 dBA – at the Flight Chamber level (PF45DL model. See noise level test here.) |
* – Idealized periodic domain of turning vanes and uniform inlet velocity profile and the following air parameters:
- Air density (ρ) = 1.225 kg/m³
- Air dynamic viscosity (µ) = 1.716 × 10⁻⁵ N*s/m²
The resistance along the length of the duct must be taken into account. See details – Airduct Corner Section Optimisation .
Heat transfer parameters
For the case where the refrigerant is water.
See Datasheet for details.
Heat Transfer Coefficient for Dry air (RH = 0%, T = 30 ˚C) | HTCL [W/m/K] v/s Air speed [m/s] 5 m/s – 24 W/m/K 20 m/s – 64 W/m/K 100 m/s – 230 W/m/K |
Heat Transfer Coefficient for Humid air (RH = 90%, T = 30 ˚C) | HTCL [W/m/K] v/s Air speed [m/s] 5 m/s – 73 … 172 W/m/K 20 m/s – 87 … 191 W/m/K 100 m/s – 104 … 213 W/m/K depending on the water supply pressure. |
| Cooling channel area to vane cross-section ratio | > 45% |
Power Requirements
| Additional pressure drop generated by the cooled turning vane active cooling system | 0 Pa * |
Cooling system consumption | Independent chiller, according to client’s cooling needs |
* -Considered in the resistance of the wind tunnel with closed flaps of passive ventilation (the most efficient mode of operation without accelerated air ejection).
Hydraulic Network Parameters
| Coolant channels | 3 |
| Inlet and outlet ports | 6 |
| Connection | Flexible hose & DIN connector |
| Allowed coolant types | Water (all data here is given for this type). Propylene glycol and other ASHRAE aluminum compatible refrigerants. |
| Hydraulic resistance | see Datasheet, Table A.3.1. |
Water flow rate Q vs pressure drop ΔPwater (kPa) btw, inlet and outlet vane ports. For all channels of 1 vane. For a vane length of 4m. Other options – see Datasheet. | 5 kPa – 2.39 m3/h 10 kPa – 3.37 m3/h 30 kPa – 5.85 m3/h 100 kPa – 10.62 m3/h |
Max. coolant (Water) pressure difference | ΔPWATER = 500 kPa |
Absolute burst pressure of the coolant channels (long term) | PBURST = 600 kPa |
Test pressure of flange welding leak tightness (impulse) | PFLTEST = 2000 kPa |
Tunnel Tech’s aerodynamically optimized turning vanes offer unparalleled versatility and efficiency, suitable for a wide array of applications where airflow management is crucial. Our customizable air guide vanes are designed to integrate seamlessly into various systems, reducing energy consumption, minimizing noise, and optimizing aerodynamic performance. Below, we explore the diverse applications of our turning vanes, highlighting their benefits across different industries and scenarios.
Wind Tunnels
- Indoor Skydiving Facilities
- Aerospace Testing
- Automotive
- Enhance the flying experience with reduced turbulence and energy-efficient operation
- Achieve precise airflow control for accurate aerodynamic testing
- Aerodynamic Testing Optimize vehicle design with improved airflow management
HVAC Systems
- Commercial Buildings
- Residential Complexes
- Data Centers
- Ductwork optimization; Energy efficiency; Reducing operational costs; Enhancing health and safety by efficiently managing air quality and temperature
- Ensure comfortable living environments with optimal air quality and flow; Enhancing health and safety
- Thermal management airflow vanes maintain critical temperature and humidity levels for server performance and longevity
Civil Engineering Ventilation Systems
- Hospitals and Healthcare Facilities
- Educational Institutions
- Quiet operation turning vanes provide vital air quality control to protect patients and staff
- Enhancing health and safety by efficiently managing air quality and temperature
- Create conducive learning environments through improved air circulation
Environmental Control
- Electronics Bio-tech Food-tech and other Hi-tech Facilities / Clean Rooms
- Sporting Arenas
- Regulate temperature and humidity for high-tech and demanding production; Air conditioning guiding vanes maintain stringent airflow standards for manufacturing and research
- Ensure comfort and safety for athletes and spectators alike
Industrial and Specialized Applications
- Tunnel Construction and Maintenance
- Industrial Facilities
- Foundries and heavy-duty facilities
- Marine Engineering
- Mining and Underground construction
- Improve air quality and safety for workers in tunnel environments
- Ductwork optimization; Energy efficiency; Sustainable development; Reducing operational costs
- Energy efficiency; Reducing operational costs; Waste heat energy recuperation; Decarbonization and ESG; Heavy-duty HVAC air ducts; Thermal management;
- Enhance ventilation systems on ships and submarines for crew comfort and equipment reliability
- Provide crucial ventilation to mining sites and other underground structures reducing the risk of hazardous conditions
Turning vanes for Waste Heat recuperation
Cooled turning vanes with integrated heat exchange channels offer a versatile solution for waste heat recovery across a variety of applications. When integrated into heat exchange systems, these vanes can capture excess thermal energy that would otherwise be lost, transferring it to heat recuperation systems, thereby significantly enhancing overall system efficiency.
In practical applications, this technology can be utilized in multiple areas. For instance, in industrial processes, cooled turning vanes can recover waste heat from exhaust gases and redirect it to preheat incoming fluids or air, thereby reducing energy consumption. In HVAC systems, similar principles are employed through devices like heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs), which transfer heat between exhaust and incoming air streams. This process minimizes the energy required to heat or cool incoming air, leading to substantial energy savings.
Cooled turning vanes can be integrated into systems used in power generation and renewable energy sectors. For example, in combined heat and power (CHP) systems, waste heat from electricity generation is recovered and used for heating purposes, improving the overall efficiency of the system. In geothermal energy systems, these vanes can help manage the thermal energy extracted from the earth, optimizing the heat transfer processes.
In green and renewable energy initiatives, waste heat recovery plays a critical role in reducing carbon footprints and enhancing the sustainability of energy systems. This approach aligns with lean manufacturing principles by improving resource efficiency and reducing operational costs through effective heat management. Furthermore, in ESG projects, incorporating such technologies demonstrates a commitment to minimizing environmental impact and optimizing resource use, aligning with broader sustainability goals.
Heat recuperation - Related projects
Tunnel Tech has extensive experience in implementing projects involving heat exchange and HVAC systems designed for waste heat recovery using cooled turning vanes. By integrating these vanes into heat exchange setups, engineered to capture and repurpose thermal energy that would otherwise be lost, Tunnel Tech enables more effective recovery of waste heat from various industrial and commercial processes. This approach not only improves energy efficiency but also supports sustainability goals by reducing energy consumption and operational costs.
Noise reduction
If the product being developed is silent and energy efficient, then such a solution is much easier to sell. This is especially important when constructing powerful objects, such as indoor skydiving wind tunnels or powerful HVAC systems, located near residential areas where the restrictions on noise level are mandatory. Such solutions with noise damping turning vanes as air dyne are well known for use in general-purpose HVAC ducts.
TunnelTech silent turning vanes can be used for noise cancellation in conventional low air speed ventilation systems as well as in the powerful industrial ducts with high flow rates where air cooling or heat recovery is required.
Each of these applications benefits significantly from the advanced design and functionality of TunnelTech’s turning vanes, marking a leap forward in efficient airflow management. By choosing TunnelTech’s low-drag air guiding vanes, clients can expect to confidently meet or even exceed their system performance goals, all while
- reducing energy consumption * by up to 30%
- reducing noise * by 60%, compared to conventional air ducts.
* – experimental results for the TT45Pro wind tunnel geometry.
For inquiries and more details on how our turning vanes can be tailored to fit specific needs, please reach out to our team. Let TunnelTech be your partner in achieving optimal airflow management solutions.
| Tunnel Tech Turning Vanes - Datasheet | ||||||||
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Technical information on Tunnel Tech wind tunnel corner section assemblies and turning vane parameters is available in a comprehensive datasheet for TTE-TSA and TTE-TV products. The documentation contains information on design options, local resistances for horizontal and vertical 90-degree flow turning corners, as well as hydraulic and heat transfer parameters for Tunnel Tech's cooled turning vanes. Download here: Tunnel Tech turning vanes - TTE-TSA datasheet |
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