OVER THE YEARS, INDUSTRIAL PROCESSES HAVE GROWN HOTTER TO BOOST EFFICIENCY. That means fans increasingly operate at higher temperatures. They usually run at high speeds with light radial loads, moving air filled with particulates that settle unevenly on an impeller and move it out of balance.
According to SKF USA Inc., all this tends to heat up bearings, shortening bearing lubrication life and causing bearing failures that lead to unplanned fan downtime and production losses. No wonder SKF says it receives at least one urgent phone call daily about heat-related fan problems.
So SKF has launched an upgrade service that it says can prolong bearing and lubricant service life while lowering maintenance costs and improving the sustainability of industrial fans. The upgrade combines an automatic circulating lubrication system with a toolkit of optimized bearings, housings, and seals.
The company estimates that lubrication issues are the source of 36 percent of all premature bearing failures. SKE use a centralized system to deliver precise amounts of grease to each fan on the system while avoiding over-lubrication.
The company's bearing toolkit typically combines self-aligning bearings with plummer block housings and specialized seals to help manage heat. The plummer block housing are designed to draw heat away from the bearing while providing precise, high stiffness support.
The self-aligning bearings combine the company's CARB toroidal roller bearing in the non-locating position and a spherical roller bearing in the locating position. The toroidal bearing accommodates the thermal expansion of the fan shaft, reducing friction, temperature, vibration, and power consumption while supporting higher fan speeds.
SKF also provides condition monitoring systems. These range from basic units that warn of potential bearing failure to more advanced predictive maintenance systems.
Thursday, 10 December 2009
Wednesday, 9 December 2009
Blending Fuels to Boost Efficiency
RESEARCHERS AT THE UNIVERSITY OF WISCONSIN-MADISON SAY THAT BLENDING DIESEL FUEL WITH GASOLINE CAN IMPROVED DIESEL ENGINE FUEL EFFICIENCY by an average of 20 percent while meeting U.S. government emissions mandates without costly pollution control equipment.
While fast-response fuel blending technology would require modification of diesel engines and separate fuel tanks for diesel and gasoline, it would use fuels readily available at the pump today. Rolf Reitz, a mechanical engineer who led the research, said the technology can also be applied to gasoline engines.
If all internal combustion vehicles were converted to dual fuel engines as efficient as his most efficient prototype - 53 percent - Reitz estimates that the United States would save on-third of all petroleum used for transportation, or roughly 4 million barrels per day.
Industry is apparently listening. The Department of Energy and University of Wisconsin's Diesel Emissions Reduction Consortium, which includes 24 industry partners, are funding Reitz's research.
Fast-response fuel blending calls for mixing the two fuels inside the engine's combustion chamber. Ordinarily, gasoline does not burn in a diesel engine because it is less reactive than diesel fuel. When Reitz sprays the two fuels into the combustion chamber together, however, the diesel ignites the gasoline.
The blending technology matches the diesel-gasoline ratio to operating conditions. Under heavy loads, such as accelerating or climbing a hill, the fuel mix might go as high as 85 percent gasoline. Under lighter cruising loads, the percentage of gasoline would fall to 50 percent.
According to Reitz, the mix enables diesel engines to operate up to 40 percent cooler, which reduces energy loss through thermal transfer. Better yet, controlling the diesel-gasoline ratio not only improves burn efficiency but also reduces emissions. In fact, it enables trucks to meet particulate and nitrogen oxide emission levels mandated by the Environmental Protection Agency without buying expensive catalytic reduction or exhaust gas recirculation equipment.
Reitz used computer models to develop the blending strategy. This enabled him to run thousands of simulations and optimize his power strategies before testing the technology on a Caterpillar heavy-duty diesel engine. The tests confirmed the model's predictions. The best tests achieved 53 percent thermal efficiency, 20 percent higher than conventional diesel engines. In fact, it was higher than today's gold standard for commercial engines, the turbocharged two-stroke diesels used in maritime shipping.
"Even more striking, the blending strategy could also be applied to automotive gasoline engines, which usually average a much lower 25 percent thermal efficiency," Reitz said. " Here, the potential for fuel economy improvement would even be larger than in diesel truck engines."
While fast-response fuel blending technology would require modification of diesel engines and separate fuel tanks for diesel and gasoline, it would use fuels readily available at the pump today. Rolf Reitz, a mechanical engineer who led the research, said the technology can also be applied to gasoline engines.
If all internal combustion vehicles were converted to dual fuel engines as efficient as his most efficient prototype - 53 percent - Reitz estimates that the United States would save on-third of all petroleum used for transportation, or roughly 4 million barrels per day.
Industry is apparently listening. The Department of Energy and University of Wisconsin's Diesel Emissions Reduction Consortium, which includes 24 industry partners, are funding Reitz's research.
Fast-response fuel blending calls for mixing the two fuels inside the engine's combustion chamber. Ordinarily, gasoline does not burn in a diesel engine because it is less reactive than diesel fuel. When Reitz sprays the two fuels into the combustion chamber together, however, the diesel ignites the gasoline.
The blending technology matches the diesel-gasoline ratio to operating conditions. Under heavy loads, such as accelerating or climbing a hill, the fuel mix might go as high as 85 percent gasoline. Under lighter cruising loads, the percentage of gasoline would fall to 50 percent.
According to Reitz, the mix enables diesel engines to operate up to 40 percent cooler, which reduces energy loss through thermal transfer. Better yet, controlling the diesel-gasoline ratio not only improves burn efficiency but also reduces emissions. In fact, it enables trucks to meet particulate and nitrogen oxide emission levels mandated by the Environmental Protection Agency without buying expensive catalytic reduction or exhaust gas recirculation equipment.
Reitz used computer models to develop the blending strategy. This enabled him to run thousands of simulations and optimize his power strategies before testing the technology on a Caterpillar heavy-duty diesel engine. The tests confirmed the model's predictions. The best tests achieved 53 percent thermal efficiency, 20 percent higher than conventional diesel engines. In fact, it was higher than today's gold standard for commercial engines, the turbocharged two-stroke diesels used in maritime shipping.
"Even more striking, the blending strategy could also be applied to automotive gasoline engines, which usually average a much lower 25 percent thermal efficiency," Reitz said. " Here, the potential for fuel economy improvement would even be larger than in diesel truck engines."
Monday, 7 December 2009
Computing
This section was written by Associate Editor Jean Thilmany
SUPERCOMPUTER UPGRADE
Cystorm, Iowa State University's second supercomputer, has a peak processing rate about five times that of the university's other super system, CyBlue, but giving up an idea of how fast computer power is advancing, Cytorm didn't make the cut for the current list of the top 500 computers in the world. CyBlue, on the other hand, was rated 99th in the world when it first booted up three years ago.
The new supercomputer, a Sun Microsystems machine, is capable of a peak performance of 28.16 trillion calculations per second. The supercomputer, which went online in August, will help Iowa State researchers advance their work in materials science, power systems, and systems biology.
"cystorm is going to be very good for data-intensive research projects," said Srinivas Aluru, the Ross Martin Mehl an Marylyne Munas Mehl Professor of Computer Engineering and the leader of the Cytorm project. "The capabilities of Cytorm will help Iowa State researchers do new research in their fields."
CyBlue, an IBM Blue Gene/L supercomputer on campus since early 2006, uses 2,048 processors to do 5.7 trillion calculations per second. Cytorm has 3,200 processor cores, Aluru said.
The new machine also scores high on a test of actual running performance, using the same test that is used to rank the Top 500. It clocked in at 15.44 trillion calculations per second, compared to CyBlue's 4.7 trillion per second. That measure makes Cytorm 3.3 times more powerful than CyBlue, Aluru said.
Those performance numbers, however, do not earn Cytorm a spot on the current Top 500 list of the world's fastest supercomputers. The list, compiled by prominent researchers and issued twice a year, confers bragging rights on research institutions and manufactures, and serves as a tool to track trends in supercomputers. It is published online at www.top500.org.
No. 500 on the current list is an IBM BladeCenter HS21 cluster, operated by Financial Services in the U.K., with a peak performance of 37.64 trillion calculations per second. Its actual running performance, or Rmax, which determines the computer's world ranking, is 17.09 trillion calculations per second. No. 1 is the U.S. DOE's Roadrunner, an IBM BladeCenter QS22 cluster with an Rmax of 1,105 teraflops.
SUPERCOMPUTER UPGRADE
Cystorm, Iowa State University's second supercomputer, has a peak processing rate about five times that of the university's other super system, CyBlue, but giving up an idea of how fast computer power is advancing, Cytorm didn't make the cut for the current list of the top 500 computers in the world. CyBlue, on the other hand, was rated 99th in the world when it first booted up three years ago.
The new supercomputer, a Sun Microsystems machine, is capable of a peak performance of 28.16 trillion calculations per second. The supercomputer, which went online in August, will help Iowa State researchers advance their work in materials science, power systems, and systems biology.
"cystorm is going to be very good for data-intensive research projects," said Srinivas Aluru, the Ross Martin Mehl an Marylyne Munas Mehl Professor of Computer Engineering and the leader of the Cytorm project. "The capabilities of Cytorm will help Iowa State researchers do new research in their fields."
CyBlue, an IBM Blue Gene/L supercomputer on campus since early 2006, uses 2,048 processors to do 5.7 trillion calculations per second. Cytorm has 3,200 processor cores, Aluru said.
The new machine also scores high on a test of actual running performance, using the same test that is used to rank the Top 500. It clocked in at 15.44 trillion calculations per second, compared to CyBlue's 4.7 trillion per second. That measure makes Cytorm 3.3 times more powerful than CyBlue, Aluru said.
Those performance numbers, however, do not earn Cytorm a spot on the current Top 500 list of the world's fastest supercomputers. The list, compiled by prominent researchers and issued twice a year, confers bragging rights on research institutions and manufactures, and serves as a tool to track trends in supercomputers. It is published online at www.top500.org.
No. 500 on the current list is an IBM BladeCenter HS21 cluster, operated by Financial Services in the U.K., with a peak performance of 37.64 trillion calculations per second. Its actual running performance, or Rmax, which determines the computer's world ranking, is 17.09 trillion calculations per second. No. 1 is the U.S. DOE's Roadrunner, an IBM BladeCenter QS22 cluster with an Rmax of 1,105 teraflops.
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