mechanical engineering
design 2004
news & notes
an insect's knack
for combustion
A species of beetle that squirts its predators
with a high-pressure spray of boiling liquid could provide the key to
significant improvements in aircraft engine design. Researchers are looking
at the bombardier beetle's unique natural combustion technique with an
eye toward copying it for use in the aircraft industry.
Scientists at the University of Leeds in Leeds, England, are studying
the bombardier beetle's jet-based defense mechanism because they
hope that its natural system will help solve a problem that can occasionally
occur with man-made systems operating at high altitudes. They're
studying the beetle in the hope that it will teach them how to reignite
a gas turbine aircraft engine in temperatures as low as -50°C after
the engine has cut out, said Andy McIntosh, professor of thermodynamics
and combustion theory at the university.
The insect defends itself by squirting predators, such as ants, frogs,
and spiders, with a high-pressure jet of boiling liquid in a rapid-fire
action called pulse combustion. The Leeds researchers hope the project,
which is funded by the Engineering and Physical Sciences Research Council
of Swindon, England, will help them better understand the beetle's
unique pulse combustion and nozzle ejection mechanism.
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| The bombardier beetle's natural defense mechanism is inspiring scientists. |
They also aim to identify how combustion engineers may exploit that understanding
to practical effect. For instance, engineers might develop a device that
helps relight aircraft engines at high altitude by accurately squirting
plasma into the engine's combustion chamber, McIntosh said.
"The bombardier beetle's defense mechanism represents a
very effective natural form of combustion," he said.
Copying such natural mechanisms is part of the growing field of biomimetics,
in which scientists learn much from intricate design features already
in nature.
In preliminary studies, McIntosh and his team have already found that
the shape of the bombardier beetle's tiny combustion chamber is
important for maximizing the amount of material ejected for each explosion—about
300 explosions per second. The shape of a natural projection on the beetle
resembling a nozzle that can swivel in any direction is also critical,
he said.
turbine designed
to harness tides
Water comprises 70 percent of the Earth's surface and contains enormous potential as a source of energy in the future. Yet hydropower accounts for only about 18 percent of the world's electrical output each year. While hydropower is a clean energy source, it requires expensive dams that flood vast areas. That's one factor keeping it from being more widely used, according to Alexander Gorlov, a professor of mechanical engineering at Northeastern University in Boston and the inventor of a turbine that would harness the power of currents and tides.
Gorlov claims that his barrel-shaped 36-by-40-inch turbine can successfully transform the forces of oceans, rivers, and bays into electricity, and just might radically change access to hydropower.
Engineers at GCK Technology of San Antonio, Texas, now produce the Gorlov Helical Turbine.
Gorlov received the ASME Thomas Edison Patent Award in 2001 for his turbine invention. GCK is a renewable-energy firm that secured worldwide rights to the patents from Northeastern University.
Gorlov's helical turbine consists of blades twisted into a helix, which is the shape of a DNA molecule. The turbine's blades rotate at twice the velocity of the water current's flow rate and they capture 75 percent more of the water's energy than a conventional turbine.
An open-river system of helical turbines should generate electricity for just $400 to $600 per kilowatt, which is much less than the cost of constructing other power-generation systems, Gorlov said. The turbine has almost no operating costs, he added.
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| The Gorlov Helical Turbine uses blades twisted into a helix, the shape of a DNA molecule. |
After Gorlov developed the helical design, GCK engineers needed to take laboratory and prototype data and turn it into a real working machine. They wanted to determine loads on the blades, the shaft, and the bearings in order to find the bearing and blade designs that would ensure the turbine could withstand the water's forces. They also wanted to reduce manufacturing costs, and ensure reliable operation.
For this type of analysis, GCK engineers hired Sigma Design Co., a Springfield, N.J., design and engineering firm that performed computational fluid dynamics and finite element analysis on the helical turbine design. Based on the analysis results, Sigma Design developed a manufacturing friendly turbine design that helped reduce the turbine's overall design cycle costs by 50 percent, said Jerry Lynch, Sigma Design's president.
Lynch and his colleagues performed the tests using computational analysis software called CosmosFloWorks and FEA software called CosmosWorks, both from SolidWorks of Concord, Mass. The Sigma team used three-dimensional design software, also from SolidWorks, to model the turbine's geometry, which Gorlov had designed by hand.
Ed Kurth of GCK said the turbine will be mass-produced from aluminum. Engineers specifically designed the turbine to be put together with common tools, so it can be readily installed in remote locations, Kurth said.
$100,000 for
putting it in reverse
For the past century, mathematicians have been using the Morse Theory to gain insight into difficult mathematical questions. Now the National Science Foundation has awarded a $100,000 grant to a software maker that will research the theory's use in reverse engineering.
In the computing world, the Morse Theory has helped researchers find discrete structure in continuous, smooth data. This is valuable, for example, in calculating and visualizing scientific phenomena such as temperature distribution in the ocean and electron densities of molecular structure.
Researchers at the software company Raindrop Geomagic think the theory can be applied to further automate reverse engineering, the process of capturing a physical object and transforming it into a surface model ready for manufacturing, said Herbert Edelsbrunner, the company's co-founder. Raindrop Geomagic of Research Triangle Park, N.C., makes software that turns physical products into digital models, a kind of reverse engineering of its own.
"We plan to use the discrete structure that arises from studying distributions as Morse functions to solve the problem of automatically extracting features in smooth surfaces," Edelsbrunner said.
The research could help deliver a sought-after advance in reverse engineering: the ability to automatically create surface patches that follow the direction and features of a triangulated model.
shipbuilder shares
design information
Designing and building a ship remains one of the most significant engineering challenges due to the large number of components involved—sometimes more than 1.5 million parts—and the spatial constraints of the vessel, according to Bruno Hamata, chief engineer at Siddhartha Sailing Yachts, a luxury boat design company located in Himburg, Austria.
To help share information between engineers and suppliers during all stages of building a new vessel, the company recently implemented product lifecycle management software. Before installing the software, the company used a variety of ways to send designs back and forth and to communicate about design changes. Employees and suppliers passed information via e-mail, fax, or, often, on foot. That approach was not only time-consuming, but it hindered real-time work by different development teams, Hamata said.
The company uses PLM software from IBM PLM Solutions of Armonk, N.Y., which is tied to a CAD system, Catia, from Dassault Systèmes of Paris.
The CAD systems include a 3-D simulation capability that includes real-time rendering of elements such as the electrical and piping systems.
briefly noted
ColumbiaSoft Corp.
of Portland, Ore., has released an upgrade to its document management
software, Document Locator 2.5.
MITCalc of Decin, Czech Republic,
has released a connection module for its mechanical calculation package,
also called MITCalc, which connects to the SolidWorks CADsystem. MITCalc
is a multilanguage mechanical and technical calculation package.
Abaqus of Pawtucket, R.I., a maker of finite element analysis software, and AVL of Graz, Austria, have signed an agreement intended to deepen the integration between the companies' software products. AVL makes mathematical simulation software, specifically for powertrain and internal combustion engine development.
The Partners for the Advancement of Collaborative
Engineering Education, a corporate alliance between General
Motors, EDS, and Sun
Microsystems, has donated CAD, manufacturing, and engineering
software, hardware, and training worth approximately $240 million to the
University of British Columbia in Vancouver.