ebm-papst Fans, Blowers and Technology

By Scott Beauchemin, Vice President – Engineering

In almost every development process, multiple design iterations are unavoidable. Optimizing an air flow system in a single iteration is rare. In fact, some projects require three or four design loops before the targeted air flow is met. In 2009, ebm-papst Inc. set out to find a way to minimize these steps and thus reduce development costs and get projects to market more quickly. The answer was Computational Fluid Dynamics (CFD) software.

Optimizing air flow systems during development can be challenging. Before ebm-papst introduced CFD to our development process, we would fabricate an initial prototype design using knowledge gained from previous projects. After testing it in the lab, we would compare the results against the air flow, efficiency and noise targets defined at the beginning of the project. In an ideal case, the results from the first prototype would meet or even exceed the targets defined for the project. But typically, the prototype would not exactly meet the targets, and we would move on to a second design. Each new iteration would require engineering time, material costs to fabricate another prototype and lab time to test the new version.  

Using CFD software has reduced the number of design iterations by allowing us to:

• Run numerical simulations of the flow field in a system using relatively basic CAD geometry to define the system. The software predicts the air flow through the system, determines the pressure drop, and helps identify problem areas in the flow field. It also looks at heat transfer to determine if critical components are being cooled adequately by the flow through the system.

• Simulate various designs to determine the optimal one for that specific system. CAD models for each design modification are created.

• Run those simulations simultaneously, often times after hours so the data is available the next morning. The various design options can be directly compared to determine which characteristics provide the best results.

CFD simulations don’t eliminate the need for experimental data. We still must build and test a prototype in the lab to verify that it meets the design targets. And we still use our knowledge from previous projects – but now, a characteristic can be simulated in the new system to see if it is beneficial. The simulations allow us to quickly narrow in on an optimized design.

The addition of CFD analysis to our capabilities has been a tremendous asset, and is just another example of how ebm-papst is constantly investigating and innovating to offer more efficient processes and solutions to our customers. To learn more, contact sales@us.ebmpapst.com.

By Armin Hauer, Advanced Technology Manager 

Two weeks ago, I joined my German ebm-papst colleagues Katrin Schaake, Wolfgang Laufer and hundreds of scientists, researchers and engineers who swarmed San Antonio to attend three powerhouse events from June 3 - 7:     

• The Air Movement and Control Association International (AMCA) engineering conference    

• The International Gas Turbine Institute (IGTI)’s annual technical congress with several hundred papers and meetings of 20 committees

• The ASME International Gas Turbine Institute’s TurboExpo 2013, which hosted vendors from 12 countries 

As a longtime corporate member, ebm-papst has actively participated in AMCA’s events and worked on its committees. Because fans and turbomachinery play an important role in aircraft engines, power plant turbines and many other applications that would be discussed at IGTI and ASME, this year AMCA decided to co-locate and co-time its conference to allow cross-pollination of ideas and expertise with the other two events. 

The scope of fan sizes explored during the AMCA conference spanned 3.6  to 157 in., speeds from 750 to 10,500 rpm, and absorbed power from 30 W to 20 MW. We fan engineers loved it! 

The AMCA schedule included Wolfgang’s presentation, “Numerical Investigation of Axial Fans in Serial Connection,” that discussed his team’s research on two-stage setups of compact cooling fans, which are used widely in electronic telecom and computing equipment. These connected fans operate mostly at part load. If one fan fails, the remaining fan will speed up to avoid a local pressure drop or recirculation in the application. 

Using 3D numerical methods, the ebm-papst team of aerodynamics engineers, led by Wolfgang, studied various two-stage set-ups of axial fans with 85 mm impeller diameters. The goal was to measure and compare steady and unsteady calculations of different serial fan configurations and compare results. 

Our team proved how a proper arrangement of two axial fans will increase both fan pressure rise and flow rate. This type of arrangement would benefit air flow through the system & enhance cooling.

Dr. Michael Schmitz, manager of aerodynamics and simulation research and development at ebm-papst-St. Georgen, is a member of IGTI’s recently created Fans and Blowers Committee. The papers sponsored by this committee highlighted fan technologies in hovercrafts and fan sound reduction techniques for locomotives. One researcher provided bio mimetic studies involving fan blades with leading-edge bumps similar to the tubercles of humpback whales. Another analyzed the tip-clearance noise of axial fans, comparing experiments with numerical simulation. Another IGTI paper discussed inverse design methodology for fans and blowers driven by a genetic algorithm. 

Other topics presented at the conference included computational fan development, innovations such as a carbon-fiber bladed fan for abrasive air streams and a pair of fire-resistant, reversible tunnel ventilation fans. 

Presentations also addressed the all-important testing and certification of fans. In addition to electrical safety, air performance, sound, overspeed, balance and vibration requirements, some fans must undergo seismic pre-qualification or high-temperature stress testing. 

A talk about permanent magnet fan motors provided a welcome refresher. In 2004, ebm-papst Inc. won the AHR Expo Innovation Award for incorporating magnetic drive technology in fans up to 50 in. diameter and 12 kW electrical input, which expanded products to a wide variety of HVAC/R applications that can benefit from these advances.  The exhibition rounded off our days with hands-on demonstrations, follow-up discussions and networking opportunities. 

Next year’s Turboexpo takes place in Düsseldorf, Germany, and we’re already looking forward to participating. 

What innovations in fan technology are benefiting your business environment? What areas can be improved for your application’s air-moving requirements? We’d love to hear from you – leave a comment and message below.

by Scott Beauchemin, Vice President - Engineering

ebm-papst’s success in the market can partially be attributed to our dedication to maintaining engineering resources to support customer projects.  Our local technical expertise allows us to provide a level of support that most competitors aren’t able to provide.  We have several engineering departments within the organization that help make that possible.

The Applications Engineering department has the highest head count of the various engineering groups at ebm-papst.  Applications Engineers are responsible for providing technical support to all customers within an assigned geographic region. Technical support can range from helping the customer select the proper air mover for their equipment to answering basic technical questions about ebm-papst product.  Applications Engineers work with customers from various market segments including HVAC, medical, industrial, IT/ telecom, etc. The diversity of our customer base gives the engineering group an opportunity to learn about various types of equipment.  Applications Engineers also spend part of their time working in our engineering lab which consists of several air flow chambers and a semi-anechoic sound room.  Customers send their equipment to our lab for baseline testing and optimization.  The Applications Engineers coordinate this effort, help perform the tests and report the results back to the customer.  The knowledge of ebm-papst product and customer’s applications gives Applications Engineers an opportunity to advance within the company if they perform well.  The educational background for an Applications Engineer is typically a Bachelor’s of Science in Mechanical Engineering.  Since our product is very much electro-mechanical, an educational background in Electrical Engineering can also be attractive. 

A portion of ebm-papst’s business is producing value-added assemblies for customers.  A value-added assembly can come in different configurations but it generally involves packaging a fan or multiple fans within a sheet metal assembly.  The assembly can include various other components such as connectors, filters and specific control boards.  While Applications Engineers serve as the project manager for these projects, there are three additional engineering groups that have direct responsibilities for these projects. 

The Design Engineering group is responsible for developing the value added assembly in Pro-Engineer and creating Bills of Material.  They are directly involved in working with the production floor regarding their designs.  The Design Engineer will often be seen building prototypes and working with their hands. Design Engineers will also conduct air flow modeling using Computational Fluid Dynamics software.  The goal is to optimize the air flow path in simulation so we only make sheet metal one time.  Design Engineers typically have a Bachelor’s of Science in Mechanical Engineering.  

The Electrical Engineering group is tasked with developing control boards that are used in conjunction with ebm-papst fans.  Members of the Electrical Engineering group will design the circuits, lay out the PCB so it can be fabricated, write software, build and test prototypes.  The controllers developed by this group are most often installed into a value added assembly but can be sold as a separate component on occasion. Members of the Electrical Engineering group generally have a Bachelor’s of Science in Electrical Engineering.

The last link in the value added chain is the Manufacturing Engineering group.  Manufacturing Engineers are tasked with supporting the production floor with work instructions, developing processes for manufactured parts and creating new tooling.  We are constantly expanding our manufacturing capabilities so the Manufacturing Engineers keep busy introducing new technology to the floor.  The Manufacturing Engineers work side by side with the Design Engineering group to bring a new product into production.  Manufacturing Engineers typically have a Bachelor’s of Science in Mechanical or Industrial Engineering.   

by Scott Beauchemin, Vice President - Engineering

An important part of ebm-papst Inc.’s business is our value-added assemblies.  These assemblies are generally customer specific sheet metal enclosures that contain one or more ebm-papst air movers.  The development process for these assemblies is very much a collaborative effort between ebm-papst and our customer.  Our goal is to create a cost-effective design that meets customer requirements and can be easily manufactured on our production floor.

A critical phase in the development process is the initial design review.  At this stage, a cross-functional team of engineers is assembled to evaluate the product and offer input into the design.  We use historical knowledge from previous products to avoid design characteristics  that may have caused issues in the past.  Our philosophy is to avoid failures by designing them out.  The product is modeled in Pro-Engineer which also allows us to get an idea of how easy the product will be to assemble.  As the type of projects we work on has evolved, we have implemented Computational Fluid Dynamics simulations into the process to optimize the air flow path before making our first prototype. 

Despite all the planning in the development phase, input from the first prototype build will be used to tweak the design.  Every product we build evolves throughout the life of the product.  Our production staff that build the product day-in and day-out provide regular feedback on how to improve the design.  Nothing replaces the feedback you get from the people that build the product.   At the end of the day, there is a feeling of satisfaction you get from seeing a product being built 10 years after you worked on the project!