Leveraging CFD through Ansys Discovery and its new features for 2025 to Tackle Challenges in the HVAC Industry with Computational Insights.
The HVAC industry faces several challenges in designing efficient and reliable duct systems:
This is where Computational Fluid Dynamics (CFD) steps in as a game-changing tool. CFD enables engineers to visualize airflow behavior, evaluate pressure losses, and optimize designs long before physical prototypes are built. By combining experimental data with CFD simulations, the HVAC industry can move closer to achieving energy-efficient and cost-effective solutions.
The HVAC industry employs various techniques for design. While experimental data is available in handbooks, conducting real-world tests could often be time-consuming and costly. Analytical approaches, based on simplified fluid mechanics equations, are faster but often inaccurate for complex geometries. The CFD approach helps overcome design challenges while driving efficiency and innovation in the HVAC industry.
Methods
Ansys Discovery offers advanced tools and features to streamline CFD simulations, enhancing both efficiency and accuracy. It has three modes to complete a design: 1) MODEL is the CAD tool to create, modify or repair geometries that can be imported in different formats, 2) EXPLORE is the Live Physics GPU Solver that allows obtaining Live Physics simulation results quickly, and 3) REFINE uses the Fluent Solver running on CPU for a greater fidelity. The following picture presents an example delevoped by Ansys experts.
A standout capability is its polyhedral meshing support, which combines speed with precision while reducing GPU memory usage. This feature excels in capturing complex geometries such as thin structures and narrow flow passages, making it ideal for applications like fluid thermal heat transfer, electronics cooling, and detailed flow control device analysis. Key features of Simulation-driven design include:
Results
There are different companies like Moffitt that already use Ansys Discovery for their simulations. In this blog, let's consider the example shown in the picture below, created in Ansys Discovery. The small building has three inner spaces, and an HVAC system has been designed based on the given requirements. This represents the initial design of the complete HVAC system. CFD analysis can be used to evaluate air distribution within the inner spaces and assess the ducting design. In this example, the focus is on the latter, analyzing the velocity and pressure fields throughout the domain. Two ducting systems are selected (intake and exhaust).
Ansys Discovery offers various tools for repairing and preparing geometry. To define the fluid domain within the ducting system, use the 'Volume Extract' tool, located under the (1) Prepare Tab. This tool enables users to (2) select all the faces enclosing the region and then (3) pick a face inside the volume. The result is (4) a new volume ready for simulation where the boundary conditions are applied. The user can keep the geometry of the walls but excluded from the simulation.
For the intake system, a single inlet boundary condition is defined with a known mass flow rate. Alternatively, it can be set as an inlet velocity with a uniform profile (normal to the boundary), defined by components, or as a swirling flow. All ends are set as outlets with a gauge pressure of 0 Pa. By default, all inner surfaces are considered smooth with a no-slip condition. The working fluid is air, with properties at 20°C, referenced from Table 2 in Fluid Mechanics by Frank White, 7th edition.
Recently, Ansys Discovery introduced a new feature that allows users to visualize and control mesh creation in EXPLORE mode. The mesh is generated based on the cell size, which is determined by both global and local fidelity values—not just the fidelity bar. Users can view the entire mesh as well as cross-sectional areas using a Cut Plane. This plane appears in the tree and can be repositioned using the Move Tool. Additionally, since 2024R2, friction drag calculations have been improved for greater accuracy, making results more reliable. The figure illustrates the different mesh distributions across various regions.
The processing time ranges from seconds to several minutes depending on the fidelity level chosen for the calculation process (see the Table below) and the available Hardware. As reference, this demo is developed using the NVIDIA T1000 (8GB) GPU Card. The calculations include mass flow-weighted average for monitors and the k-w SST turbulence model. Results for velocity and static presure are available using the 'Direction Field' Tool. The designer can easily assess the critical regions of the design. The model with a local fidelity of 5 mm on all surfaces provides a pressure drop of 9.07 Pa (solved using a better GPU Card). This suggests the advance of using mesh controls (global/local refinement).
Exhaust duct system
The simulation of the exhaust duct system follows the same procedure. However, in this case, the duct ends are defined as inlet sections with a gauge pressure of 0 Pa, while a single outlet is set with a specified mass flow rate. The results reveal recirculation in several regions of the system, allowing the designer to assess operating conditions and optimize the geometry to achieve a suitable pressure drop and uniform airflow distribution. It is worth noting that the analysis can be performed with different fluids and properties at various temperatures, as well as different inlet or outlet velocities or mass flow rates.
Regular users know that Ansys Discovery enables flow visualization using particles, providing a clearer understanding of 3D flow patterns within the domain. This feature is available through the 'Particles' tool in the results ribbon. However, the latest release introduces the ability to use multiple emitters, allowing users to track flow trajectories from specific regions—such as each inlet in this case. The tool also includes options to adjust particle size, speed, and variable range, as illustrated in the following video.
Ansys Discovery is a powerful, interactive simulation tool that revolutionizes the way engineers approach 3D modeling, design, and analysis. By combining direct modeling technology with real-time simulation capabilities, it streamlines the entire workflow—from geometry creation to in-depth physics exploration. With Ansys Discovery, users can seamlessly define and modify simulations, optimize topology, and evaluate multiple design variations with ease. The platform supports structural, fluid flow, thermal, and electromagnetic simulations, providing instant insights for faster, data-driven decision-making.
Designed for efficiency and innovation, Ansys Discovery is structured into three stages: 1) MODEL, for intuitive 3D geometry creation; 2) EXPLORE, for real-time analysis and rapid design iterations; and 3) REFINE, for high-fidelity simulations powered by Ansys Fluent and Ansys Mechanical solvers. Whether refining concepts or solving complex engineering challenges, Ansys Discovery empowers engineers to push the boundaries of design and performance. Some relevant studies are described below:
Parametric Studies
Optimization
Ozen Engineering Inc. leverages its extensive consulting expertise in CFD, FEA, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, addressing complex challenges like multiphase flows, erosion modeling, and channel flows using Ansys software.
We offer support, mentoring, and consulting services to enhance the performance and reliability of your systems. Trust our proven track record to accelerate projects, optimize performance, and deliver high-quality, cost-effective results for both new and existing water control systems. For more information, please visit https://ozeninc.com.
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