by Jerry Fireman, PTC Express

Mechanical rooms or utility rooms that house air handlers, boilers, chillers, water heaters, electrical generators, sprinkler pumps and other equipment in buildings require considerable amounts of airflow for ventilation. Yet they also must be protected from rain, snow, dust, insects, and other hazards.

Providing free flow of air while blocking solids. Designing ventilation louvers that meet these conflicting needs is a challenging task. Engineers from JAZO Zevenaar B.V., a leading producer of ventilation louvers, have to design a complex pattern of shapes that pass air freely in order to minimize the amount of ventilation required. At the same time, the louvers have to block the entry of solid objects into the rooms.

In the past, the only way to evaluate an idea for a new louver design was to build and test it, which took about three weeks and cost $4,000 to $6,000. The prototypes were often tested by standards organizations at an additional cost. If the initial design did not provide the desired results then the entire process had to be repeated. Even after testing the design, engineers would have little information about why it did or did not work because they were unable to visualize the movement of air and solids within the louver.

JAZO was not alone in using trial and error methods. Even today, only a small minority of design engineers simulate flow in their products. Flow simulation requires a deep understanding of the computational aspects of fluid dynamics in order to be certain of obtaining accurate results.

But JAZO engineers have a tradition of overcoming similar obstacles.

Embedded CFD enables software prototyping. One of the most important recent advancements made by JAZO is the use of Flomeric’s EFD.Pro computational fluid dynamics (CFD) software with Pro/ENGINEER to evaluate the performance of a virtual prototype of ventilation louvers.

The combination of these two software packages enables JAZO engineers to automate most aspects of the simulation process. They use the original Pro/ENGINEER model for CFD simulation, let the software automatically generate the CFD mesh and manage the flow parameters as object-based features residing in the Pro/ENGINEER model.

JAZO engineers have developed Pro/ENGINEER templates that automate the process of simulating the tests used by the company’s customers to evaluate louver performance.

“The template is made up of six instances, each consisting of a louver profile installed in the wind tunnel with a pre-defined wind velocity and direction,” says Henry Aaldering, Technical Director at JAZO.

New products validated in one day. The result is that JAZO engineers can design a new louver and simulate its performance in only one day. The simulation provides the same information offered by conventional testing results such as the pressure drop and ability to resist infiltration by various types of solids.

Simulation lets JAZO engineers view the flow of air and solids within the louver. This makes it possible to understand the reasons behind the performance of the proposed design and, in most cases, enables them to improve the design far more rapidly than was possible in the past.

“We have enhanced many of our existing products and can develop new products to higher standards than were possible in the past,” Aaldering says. “For example, we reduced the pressure drop of one existing product by 40 percent. Ventilation costs, for buildings, for example, can be reduced by the same proportion.”

In the first year of using Pro/ENGINEER and EFD.PRO to simulate our louver designs we continued to build physical prototypes to verify the simulation results,” Aaldering says. “But the accuracy of the simulations proved to be so good that we eliminated the need to build prototypes. In the past six months, we have generated a considerable number of new products without having to build a single prototype.”

JAZO engineers use the simulation results to create written and illustrated reports that provide all the information customers need to evaluate a new design in just a few minutes.

JAZO Zevenaar B.V. designs ventilation louvers, doors and façades for technical rooms. The company has extensive (CNC) processing facilities for working with aluminum, steel and stainless steel.