CFD analysis to predict flow development in wind turbine blade mold facility-LM Wind Power-India

PROJECT DETAILS

We carried out a Computational Fluid Dynamics (CFD) analysis of the proposed HVAC jet nozzle system for the wind turbine blade molding division at the LM Wind Power blade manufacturing facility in Bangalore, India. The facility comprises four molding bays, each supplied with cold air through two Air Handling Units (AHUs). Each AHU is connected to 40 jet nozzles, resulting in a total of 320 jet nozzles across the four bays. The primary objective of this HVAC CFD analysis was to evaluate airflow distribution within the molding bays, assess the air-impingement angles produced by the jet nozzles, and investigate the prevailing flow regimes. Understanding these flow characteristics is essential to ensure effective air distribution, minimize undesirable local air velocities, and support a safe and comfortable working environment. The flow regime is particularly important from a health and safety perspective, as it influences air movement, jet behavior, and the overall ventilation performance within the facility. Using CFD simulations, we analyzed the airflow patterns and evaluated the proposed HVAC configuration to identify potential areas for improvement. The simulation results and key observations were presented to the management team at LM Wind Power, along with engineering recommendations to improve airflow distribution and enhance the overall performance of the HVAC jet nozzle system.

The 3D CAD model of the HVAC jet nozzle system and the molding bay facility was developed in accordance with the specifications and requirements defined for the CFD analysis. The model was created using the 2D AutoCAD drawings provided by the client as the primary reference. PTC Creo CAD software was used to develop the three-dimensional geometry, incorporating the relevant structural details, HVAC ducting arrangements, Air Handling Units (AHUs), and jet nozzle configurations required for the simulation. The CAD model was suitably simplified to retain the geometrical features essential for accurate airflow prediction while minimizing unnecessary details that could increase computational complexity. Particular attention was given to the representation of the air supply and distribution system to ensure that the model adequately captured the key flow passages and boundary regions. The finalized 3D geometry served as the foundation for subsequent CFD pre-processing, mesh generation, and airflow simulation.

A computational mesh was generated for the simplified 3D CAD model described in the previous section to facilitate the CFD analysis of the HVAC jet nozzle system. The mesh was developed using the Poly-Hexcore meshing technique, which combines polyhedral cells with a hexahedral core to achieve a good balance between computational efficiency and solution accuracy. Appropriate mesh refinement was incorporated in regions expected to exhibit high flow gradients, particularly around the jet nozzles and other critical flow passages where significant variations in velocity and pressure were anticipated. This localized refinement enabled better resolution of the airflow characteristics while maintaining computational efficiency across the larger computational domain. The final mesh consisted of approximately 20 million cells and was assessed to ensure compliance with the required mesh quality criteria. The resulting mesh provided a suitable foundation for capturing the complex airflow patterns within the molding bays and contributed to achieving stable convergence of the numerical solution. This ensured that the computational resources were utilized effectively while maintaining the required level of accuracy for evaluating the airflow distribution and jet development within the facility.

The CFD analysis was carried out by configuring the supply and return air duct heights in accordance with the specifications and design requirements provided by the client. The simulations were performed to evaluate the influence of the duct configuration on airflow distribution and the overall performance of the HVAC jet nozzle system within the molding bays.The airflow was modelled as three-dimensional, steady-state, viscous, incompressible, and isothermal. The CFD simulations were performed for the specified duct height configurations to assess airflow distribution, jet trajectory, air-impingement angles, and the resulting flow characteristics within the molding bays. The simulation results provided a basis for comparing the proposed configurations and identifying potential opportunities to improve ventilation performance and support the facility's health and safety requirements.

The CFD results indicate that the airflow distribution within the wind turbine blade molding bay is generally uniform, except in the immediate vicinity of the jet nozzles, where localized variations in velocity are observed due to the discharge of air. As the air jets travel away from the nozzles, the flow develops and distributes throughout the molding bay, resulting in a relatively uniform airflow pattern across the working area. The maximum air velocity observed within the molding bay was found to be within the specified limits for the required laminar flow regime. This indicates that the proposed HVAC jet nozzle system provides a suitable airflow distribution in accordance with the design requirements. The predicted flow characteristics were evaluated to understand the air movement within the facility and to support the assessment of ventilation performance and associated health and safety considerations.

The CFD results indicate that the airflow distribution within the wind turbine blade molding bay is generally uniform, with localized variations observed in the immediate vicinity of the jet nozzles due to the high-velocity air discharge. Beyond these regions, the airflow is distributed relatively uniformly throughout the molding bay, indicating satisfactory air distribution across the working area. The maximum air velocity observed within the molding bay was found to be within the specified limits for the required laminar flow regime. These results indicate that the proposed HVAC jet nozzle arrangement meets the specified airflow requirements. The predicted flow patterns and velocity distribution provide valuable insights into the ventilation performance of the system and help assess its suitability for maintaining the desired airflow conditions within the molding facility.