How cyclone separators from IMI are ready to innovate using simulation tools

IMI, which stands for Imperial Metals Industries, is a British multinational corporation based in Birmingham. Its history began about 160 years ago, being associated with Nobel Industries (1920) and being the first to commercially produce titanium (1950). Under the motto "Breakthrough Engineering", IMI is focused on the precise control of fluid flows in various industries such as oil and gas, life technologies, transportation, industrial automation, and others. The IMI Climate Control sector (formerly IMI Hydronic Engineering) specializes in optimizing the water-based heating and cooling efficiency of residential, commercial, and industrial buildings. According to World Economic Forum, 40% of the world’s energy is consumed inside buildings.

To provide comfort and energy control inside buildings, IMI offers three product types:

• Calibration and control valves (IMI TA): enable a correct and optimized water flow rate to all end devices and dynamically regulate the flow rate depending on changing ambient conditions and requirements.
• Thermostatic control valves (IMI Heimeier): fine tuning water flows at terminal units according to room temperature changes
• Pressurization units and water quality (IMI Pneumatex): maintain water pressure inside systems in the event of temperature fluctuations. Pressure vessels allow the water to expand or contract. Mechanized control boxes control water intake and outtake from the vessel. Maintaining the water pressure reduces oxygen intake.

Among the pressurization, equalization, and control systems that IMI Climate Control offers, dirt and ferrite separators are an important part of the portfolio. The separators not only protect critical equipment such as boilers and cooling systems, but they can also reduce energy consumption by up to 20% (see pdf).

IMI Climate Control customers include HVAC planers, building owners, installers, and maintenance professionals. Common customer concerns today include energy consumption in buildings, system life cycle, and system downtime. To improve system performance and ease of maintenance, dirt, magnetite, and air separators play an important role in removing deposits and corrosion carriers. In the HVAC industry, dirt is typically removed from hydronic systems using gravity separators. A tank with a larger cross-section than the inlet pipe slows down the water flow. The lower velocity allows dirt particles to settle in the tank. Gravity separators usually have inserts that slow down the dirt particles further. Although they are easier to build and have a lower pressure drop, gravity separators quickly lose efficiency as water velocities increase.

IMI has developed hydrocyclic sludge separators to handle increasing velocities. The centrifugal force pushes the particles against the tank wall. Through downward flow and gravitation, dirt is removed from the installation.

The primary challenge is designing the inlet and vortex finder axially to each other. Cyclones normally have an outlet that is orthogonal to the inlet. In addition, the inlet is arranged at an angle to the outlet to create a water vortex.

An interesting way to design a cyclone is through an insert, see Zeparo Cyclone. It is suitable for small pipe sizes up to 2 inches. For larger sizes, the production of inserts becomes more challenging. One way to design a cyclone for large pipes is to place another container on top of the vortex finder.

We used Ansys Fluent to develop large sludge separators with hydrocyclones. We modeled the particle flow and measured the retention of particles in the separator. Compared to the laboratory tests, the pressure drop matched the simulation results. Although the particle retention in the simulation had errors of up to 15%, we found that parametric changes in the simulation models had the same effect as in the laboratory. Design iterations with pure laboratory tests can be very speculative until the right solution is found. However, finding this takes a lot of time.

Simulation allowed us to understand the water flow, pressure zones, and particle behavior in detail and make objective design decisions. With simulation, design iteration studies can be carried out digitally. Once the team has agreed on the final design, we move on to the final prototype. This process eliminates lengthy, tedious, and costly physical prototype test loops, while giving the R&D engineers a clear understanding of their product.