Taco Comfort Solutions

Transcription

1 Industrial machinery and heavy equipment Product Simcenter Heating and cooling equipment manufacturer uses STAR-CCM+ to save time and costs by rapidly simulating multiple pump designs Business challenges Design pumps that are more robust and efficient Streamline workflows Save on physical testing costs Keys to success Use STAR-CCM+ to test virtual prototypes before lab testing Use automated part swapping process for quick multi-design testing Explore digitally and confirm physically rather than the other way round Siemens PLM Software solution provides with confidence in designs before physical testing Going virtual Pumps are the unsung heroes of many aspects of our lives. They enable our water and sewage systems, ventilation systems, cooling in energy plants and many more applications to function effectively. Pump design engineers face multiple challenges when they aim to create new and better products. Pumps have to operate well over a range of conditions, meet government efficiency regulations and run reliably over long lifetimes with minimal downtime for repairs. Traditional design methods have relied heavily on testing physical prototypes. This can be expensive and time consuming, with multiple cycles of design/redesign and testing for each new product. Creating a virtual prototype enables rapid investigation of multiple pump designs over a range of possible operating conditions, which not only speeds up the design process but also reduces the costs associated with physical testing. (Taco) uses this approach to bring better pumps to market faster. Results Saved time and costs by exploring the performance of numerous digital prototypes Eliminated the iterative startover process and sped up the complete design cycle Facilitated rapid simulations and provided confidence the results would be consistent and repeatable

2 Figure 1: Example of a Taco Comfort Solutions circulator pump. When I think back a few years to the first pumps I worked on, we would order parts for testing, they would be bad and we would have to do the whole design, ordering and testing process again. Now that we are using STAR-CCM+, we are cutting out this iterative start over process and speeding up the complete design cycle. Design and simulation Taco uses STAR-CCM+ software as a virtual lab prior to creating and testing physical prototypes. Product engineer leads Taco s computational fluid dynamics (CFD) design operations. After importing the geometry from SolidWorks software, all of the meshing, simulation and analysis is performed in STAR-CCM+, as shown in figure 2. For each pump design the CFD simulation gives a full, three-dimensional representation of the flow and pressures within the pump housing. We can take readings at any point in the model, like virtual probes, explains Vandal. For example, we can pull out the static pressure or total pressure values at the same points as the probes used in the lab testing, so we can directly compare the STAR-CCM+ results with the real-world application. This validation of the CFD model gives the team a high level of confidence in the CFD results, along with the predictive insight into performance characteristics such as head, efficiency and best efficiency point (BEP) flow rate. Once Vandal and his team have three or four designs that yield acceptable performance in STAR-CCM+, they move on to building and testing their physical prototypes. Even with their ability to rapidly prototype (via 3D printing) the stereolithography (SLA) impellers, each one costs up to $2,500 to build and test. Exploring the performance of numerous digital prototypes in STAR-CCM+ provides significant cost and time savings, enabling a high probability of success in a single phase of prototype testing and ensuring a short development time window. Simulating the complete pump curve Vandal and his team run steady-state simulations on each design, testing multiple flow points to establish the BEP flow rate. In an ideal world, pumps would always run near the BEP, but this is not always the case. To prevent field problems and meet customer needs, it is important to look at off-design flow to be sure the pump will be robust over the complete operating curve. Vandal describes three distinct sections: On the left hand side of the pump curve you can get an excessive droop, which is not acceptable. The BEP Figure 2: A pump model is designed in CAD software and imported into STAR-CCM+ (left), where it is meshed (middle) and simulated (right). Our major gain from using STAR-CCM+ is shortening our iterative design process in a highly competitive industry.

3 lies in the center and on the right hand side you need to examine the operating conditions at high flow rates. Taco performs unsteady simulations in STAR-CCM+, aiming to examine the entire pump curve. We initialize the CFD model with a steady state run at BEP flow rate, then change the boundary conditions so the flow changes towards the extreme flow rate, says Vandal. He shared one example of a case that showed an underperforming design on the left hand side of the performance curve (figure 3): At off-design flow rates the pump flow can become highly unsteady (figure 4). If there is too much drop in pressure on the left hand side of the pump curve, there could be problems with operating a parallel pumping setup. I was able to run an unsteady simulation in STAR- CCM+ at 10 percent and 50 percent of the BEP flow rate in gallons per minute to quantify the amount of droop between the maximum head point (50 percent) and near shut-off head (10 percent). I used the same method to simulate alternative designs before we built the SLA impellers for lab testing. The designs that went forward for testing were those which showed good results not only at BEP, but also at low flow rate, with a smaller drop in pressure on the left side of the performance curve. Taco has confidence its pump designs can be even more robust, running as efficiently TDH (dimensionless) CFD 10% BEP 50% BEP Design target Capacity (dimensionless) Figure 3: Example of a performance curve for two test cases. Dotted lines show STAR-CCM+ results, solid lines show lab testing results. Case A showed a large drop in pressure (ΔA) between 50 percent BEP (max head) and 10 percent BEP. Redesigning the impeller (case B) decreased this pressure drop (ΔB). and reliably as possible even when operated off-design. Streamlining workflows Using STAR-CCM+ for virtual testing has sped up Taco s design workflow and reduced the costs associated with physical testing. When I think back a few years to the first pumps I worked on, we would order parts for testing, they would be bad and we would have to do the whole design, ordering and testing process again, says Vandal. Now that we are using STAR- CCM+, we are cutting out this iterative start over process and speeding up the complete design cycle. Lab Case A (bad droop) ΔA 5.5% 4.8% Case B (corrected design) ΔB 3.1% 2.4% When we first started using STAR-CCM+, we did not have much lab test data to correlate with the CFD results, so we did not know the best model settings such as roughness or leakage flows to use. We now have a library of lab test data that validates the STAR-CCM+ results, and know the best model settings to use to get accurate results. Figure 4: When the pump is operated at flow rates far off-design (left), the flow in the pump clearly becomes highly unsteady with significantly more recirculation visible compared to the flow at the BEP (right).

4 When we first started using STAR-CCM+, we did not have much lab test data to correlate with the CFD results, so we did not know the best model settings such as roughness or leakage flows to use. We now have a library of lab test data that validates the STAR-CCM+ results, and know the best model settings to use to get accurate results. But Taco is determined to streamline their design process still further. We are always looking for ways to use the software faster, comments Vandal. Any time we spend a couple of hours on something we will say how can we do this in 50 minutes? We want to work smarter with the software, not harder. Vandal and his team have worked closely with their Siemens dedicated support engineer (DSE) to streamline their simulations. It s great having a dedicated contact at Siemens who knows our processes and works with us to find solutions, explains Vandal. Taco worked together with their DSE to develop a quick multi-design testing process using the STAR-CCM+ part-swapping capability. Once the model has been set up and run in STAR-CCM+, part swapping enables Vandal to replace just the impeller or volute with an alternative design, while the CFD model settings and boundary conditions remain unchanged, as in figure 5. STAR-CCM+ then rapidly regenerates the mesh, and computes a new solution. We use a standardized naming convention in SolidWorks, so when I want to change one part in the STAR-CCM+ model, I literally hit the replace part button and run a new simulation, says Vandal. We love working this way, as we can test multiple cases one after the other using the same mesh and simulation settings. This not only makes it quick to run multiple simulations, but also gives us confidence that the results will be consistent and repeatable. Taco has also created Java macros to automate the mesh-and-run process, enabling pump curves to be generated automatically. Automated processes like this help Taco work toward their aim of halving their current design process time. Taco is also looking to the future, aiming to build on the knowledge garnered over the last two years. Greg Case, chief technology officer (CTO), says, We are relying on our strategic use of CFD simulation to help us beat our competition to market with better performing pumps, and increase market share. Vandal explains, Our major gain from using STAR-CCM+ is shortening our iterative design process in a highly competitive industry. We want to know that when we invest in lab testing efforts or part tooling, the results will have a high likelihood of success. STAR-CCM+ gives us the confidence that is the case. Essentially, we want to eliminate the feedback loop between lab testing and the design stage so that each pump design has as few lab tests as possible. Figure 5: Part swapping allows quick changes to the impeller, keeping the rest of the geometry the same. Results are easily comparable as all mesh and physics settings are identical.

5 Solutions/Services STAR-CCM+ siemens.com/star-ccm-plus Customer s primary business is an International Organization for Standardization (ISO) 9001 manufacturer of heating and cooling equipment, accessories and systems. The firm manufactures a range of highly efficient pumps and valves used in both residential and commercial spaces. Taco is committed to sustainability so it focuses on building energy-efficient products. Customer location Cranston, Rhode Island United States We want to explore digitally and confirm physically rather than the other way around. Given the library of SLA lab test data we now have using both SLA and metal parts, and the confidence we have in the STAR-CCM+ data we have generated so far, I want to aim for a future where we no longer use SLA testing but go straight from STAR-CCM+ to metal impeller testing. It is a bit risky, but I think it is possible and will save us time and costs, enabling us to bring new, more efficient and reliable pumps to market faster. We are relying on our strategic use of CFD simulation to help us beat our competition to market with better performing pumps, and increase market share. Greg Case Chief Technology Officer Siemens PLM Software Americas Europe +44 (0) Asia-Pacific Siemens Product Lifecycle Management Software Inc. Siemens and the Siemens logo are registered trademarks of Siemens AG. Femap, HEEDS, LMS, LMS Imagine.Lab, LMS Imagine.Lab Amesim, LMS Samtech, LMS Samtech Caesam, LMS Samtech Samcef, LMS SCADAS, LMS SCADAS XS, LMS Smart, LMS Soundbrush, LMS Sound Camera, LMS Test.Lab, LMS Test.Xpress, LMS Virtual.Lab, Simcenter, Simcenter 3D, STAR-CCM+ and Teamcenter are trademarks or registered trademarks of Siemens Product Lifecycle Management Software Inc. or its subsidiaries in the United States and in other countries. SolidWorks is a registered trademark of Dassault Systèmes SolidWorks Corporation. Java is a registered trademark of Oracle and/or its affiliates. All other trademarks, registered trademarks or service marks belong to their respective holders A3 10/17 H