One of the most difficult challenges in pintle-controlled rocket design is configuring the nozzle so the gas pressure at the nozzle exit is equal to the outside air pressure in order to maximize thrust. Engineers at Stone Engineering Company (SEC) in Huntsville, Alabama, are reducing design time and cost by using computational fluid dynamics (CFD) rather than physical testing to determine the optimum configuration. CFD allows us to look inside our design to gain a far greater understanding than we were ever able to achieve with physical testing results alone in the past. The result is that we can see exactly where flow separation occurs for various nozzle geometries and fine-tune our design to maximize thrust under a wide range of flow conditions.

SEC provides technical support to the U.S. Army Missile Command and Space and Strategic Defense Command in the areas of propulsion and structures. The company has extensive "hands-on" experience in the analysis, design, development, and testing of solid, liquid, hybrid, and gel propulsion systems, metallic and composite structures, and gas generators. Extensive capabilities in structural analysis, ballistic prediction, combustion instability analysis, as well as an in-depth understanding of the requirements for today's systems place SEC in a position to move forward in our fields of expertise. One of our most interesting current projects is a bipropellant gel rocket engine that uses an axial pintle to control the throat area and hence the motor thrust. The use of the movable pintle to control the throat area provides the potential to promote higher efficiency in the lower-thrust sustain phase of the motor burn, and provides a flexible response to the requirements of the application.

Caterpillar is a world leader in the manufacture of heavy equipment such as track-type tractors, wheel loaders and off-highway trucks, all requiring highly sophisticated torque converters in their power transmission devices. In its Transmission Business Unit (TBU), which designs and manufactures these torque converters, engineers use CFD to evaluate a wide range of possible designs to reach the best possible efficiency, quality and durability at the lowest possible cost.

The most crucial components of a torque converter are the impeller, turbine and stator wheels, which are arranged in a closed loop. Finding the correct blade shapes is a major iterative effort involving: 3-D blade geometry specification, 1-D converter performance and thrust prediction, and 3-D CFD analysis of the oil flow in the converter.

We use CFX-TurboGrid and CFX-TASCflow for our CFD analysis. CFX-TurboGrid’s ‘templates’ greatly reduce our grid generation effort and allow us to create high-quality 3-D grids for the three bladed passages with minimum effort.

Fluent Inc., Optimum Power, and Hewlett Packard have come together to present a free workshop featuring the latest technology in engine modeling. By coupling the innovative 1D gas dynamics modeling capabilities within VIRTUAL ENGINES with the full 3D moving mesh simulations in FLUENT6, you can apply "the best of both worlds" to your own modeling process, which means more accurate simulations used earlier in the design cycle.

To find out more about this workshop and about your chance to see live demonstrations of the products, learn about new and upcoming functionality and see industrial validation cases, visit: http://www.fluent.com/solutions/automotive/seminar /

We look forward to meeting you!

“EASA provides an intuitive Web-based environment through which users can access any software application, commercial or in-house. This makes it possible to expand access to a company’s software tools without providing specialized user training and greatly simplifying deployment and maintenance,” said Sebastian Dewhurst, Vice President, Enterprise Applications for AEA Technology Engineering Software. The new version offers the ability to include 3D graphics within the custom applications created in the EASA environment. It also provides several new user interface options and a graphical tool that greatly simplifies linking the EASA applications to underlying software. Finally, EASA 2.0 includes a new optimization module that automatically searches a defined parametric space for the optimal solution as defined by the user.

Electronics cooling simulation is helping a major aerospace manufacturer reduce design time while minimizing system weight. Thermal management is important for safe and reliable operation of all electronic equipment, and is especially so for airborne systems. Yet it can take several months and cost on the order of $10,000 to build and test a single prototype for certain equipment. For Hamilton Sundstrand, a maker of power modules for aerospace and marine applications, these obstacles have been overcome by using computational fluid dynamics (CFD) software to evaluate the effectiveness of different designs. By using simulations to better understand the airflow within each proposed device, engineers can determine the best methods for heat removal before the first prototype is built. In this manner, the company can often find novel ways to improve thermal management while reducing component weight.

During the past several years in all sectors of the electronics business, system functionality has been steadily increasing while system size has been steadily decreasing. The combination of these trends has led to a steady increase in the amount of heat generated per unit volume. Removing internally generated heat requires an effective path along which the heat can flow from the heat-dissipating components to the surroundings. To meet this need, a variety of cooling techniques is available to design engineers including, for example, conduction, natural convection, forced-air cooling, radiation cooling, and liquid cooling. Selecting and eventually optimizing thermal management has relied on, traditionally, building a series of physical prototypes using different cooling methods, and measuring the performance of each.

The speed in which CFdesign uses native MCAD models to analyze and qualitatively compare design variations is what sets CFdesign apart from traditional CFD applications. On average, implementing CFdesign can reduce the time it takes to develop, test, and prove a new product design by 70% while also reducing the costs associated with staff time and materials by 65%.