Technical Innovations
Manufacturing software from CFX
 CFX-5.5 from the CFX division of AEA Technology provides solutions to many rotating machinery applications. Any combination of meshes can be used, and multiple frames-of-reference allow the analysis of situations involving domains that are rotating relative to one another. |
Building on its meshing and solver technology, CFX, a division of AEA Technology, has released CFX-5.5, the latest addition to its computational fluid dynamics (CFD) software. According to the company, the new software provides a more efficient method for free-surface modeling relevant to applications such as marine hydrodynamics, tank sloshing, and hydraulic engineering. A new method for sharp capturing of the gas-liquid interface enables improved accuracy and solution efficiency.
The software's automated unstructured meshing capability has been improved with new 3-D proximity sensing and a "greater tolerance" to certain CAD problems to achieve a faster quality mesh. "CFX-5.5 will optimize every aspect of fluid-flow design within (the customer's) overall design and manufacturing process," said Chris Reid, President and CEO of CFX.
CFX-5 has been used by designers in both chemical and manufacturing industries to quickly generate meshes. A new generalized gird interface capability has enhanced CFX-5's geometric flexibility to enable users to generate independently a set of meshes for different sections of a problem using any tools or mesh structure within each component. The individual grids can then be combined into a single model. This and other new features of the software are supported by the coupled multigrid linear solver and scalable parallelization to contribute to a reduced design-cycle time.
 Multiple frames-of-reference with frozen rotor and the SST turbulence model were used to analyze this mixer impeller. |
For process applications, the new software extends its multiphase modeling capabilities by enabling energy and minor species to be transported and exchanged between phases and with other models. This feature makes it possible to improve the efficiency of equipment such as reactor vessels, contact tanks, bubble columns, and fluidized beds. New single- and multi-step models simulate single chemical reactions in combusting or reacting flows. The software solves all species with the coupled algebraic multigrid solver to accelerate convergence.
CFX-5.5 also offers a more advanced turbulence model than its predecessor, an SST model combined with automated wall functions. The predictions of difficult effects such as flow separation and heat transfer enhances the use of industrial flow simulations. CFX-5.5 also includes a completely new postprocessor that uses an updated graphical-user interface, which runs on Windows and UNIX platforms. The postprocessor has direct access to flow solver data structures for quantitative post-processing. It can be programmed with scripting language so that repetitive optimization or review tasks found in design environments can be automated.
- Jean L. Broge
Hydraulic rotary actuator from Helac
 Helac Corp.'s new L20 Series of hydraulic rotary actuators with 180° rotation were designed for industrial utility vehicles in applications such as the rotation of aerial work platforms and man-baskets. |
The L20 Series of hydraulic rotary actuators for industrial utility vehicles from Helac Corp. were designed as a compact, lightweight, high-torque alternative to hydraulic cylinders. The actuators, part of Helac's new LoadBear product line, have integral, glass-fiber-reinforced nylon bearings that can support and rotate heavy loads without the need for additional, external bearings. The shaft flange with drilled and tapped bolt circle permits loads to be securely bolt-mounted directly to the actuator. The 4140 alloy steel shaft also features a hollow bore that reduces weight and can be used as a secondary load path or passage for piston rods, hydraulic hoses, or electrical wiring.
The L20 actuators consist of a housing, end cap, the central shaft, and the annular piston, the latter two being the only moving parts. Helical splines machined on the shaft engage matching splines on the inside diameter of the piston. The outside diameter of the piston carries a second set of opposite-hand splines that engage with matching splines in the housing. As hydraulic pressure displaces the piston axially within the housing—similar to the operation of a hydraulic cylinder—the splines cause the shaft to rotate. According to Helac, this sliding-gear operating principle eliminates unbalanced forces, such as the inherent separating forces characteristic of rack-and-pinion actuators. Because all gear teeth remain engaged at all times, loads are evenly distributed over all splines.
Zero-leakage seals eliminate internal bypass and external leakage in the actuators. The elimination of leakage enables accurate positioning without drift. A foot-mounting configuration with 180° rotation is standard. Five models are available with torque output to 4410 N•m at 21 MPa (3250 lb•ft at 3 ksi).
- Jean L. Broge
