Once those trials are completed, the engine will travel to General Electric's Peebles, Ohio, facility in August for crosswind and acoustic testing. Limited performance trials also will be run. From article below. . .
I suggest the Peebles area is blocked to discourage industrial/ChiCom espionage on GE engine facility.--
Phil
"...the engine will travel to General Electric's Peebles, Ohio, facility in AUGUST for crosswind and acoustic testing."
"Brush seal technology is another innovation being pursued under Tech56, and a set of the seals is being evaluated for endurance and durability in a CFM56-5B now running at PEEBLES."
Boeing, Airbus Say 'No'
To New CFMI Designs
STANLEY W. KANDEBO/PEEBLES, OHIO
Though based on financial considerations, the decision underscores the aversion to risk that now permeates the industry
CFM International's airframe customers have vetoed the engine maker's proposals to pursue development and certification of advanced, new centerline engines at this time, citing customer satisfaction with the company's current stable of offerings.
Tech56 six-stage advanced high-pressure compressor employs forward-swept rotors and integrally bladed disks.
The rejection of new centerline powerplants means that technologies developed and matured under CFMI's three-year Tech56 effort are likely to be banked against future emerging needs. The engine maker had planned to use them in the near term to develop new powerplants and to freshen its current product line.
ACCORDING TO CFMI President Gerard Laviec, "we talked to Boeing and Airbus and consulted the order books. Those books today say the airlines are satisfied with our current products and with the commonality they offer." He added, however, that CFMI would continue to evaluate the marketplace with the transport manufacturers to decide when it will be appropriate to introduce updates and make changes to the fleet. That could be some time, though, given current conditions. Airbus is focused on its A380 mega-transport, and Boeing Chairman/CEO Philip M. Condit said late last year that he didn't foresee his company manufacturing a completely new transport for some 8-10 years (AW&ST Nov. 20, 2000, p. 39).
Having accepted the reality of the situation, "CFMI, at this time, will make its new technology as durable as possible so that when airlines have a desire for it, it will be in place, " Laviec said.
The engine maker has been examining advanced fans, improved compressors, low-emissions combustors and reduced-parts-count, increased-efficiency turbines under Tech56. A bevy of tests concluded last year and earlier this year indicates that virtually all the concepts will be successful. As a result, many Tech56 efforts this year are making the transition from technology development to technology maturation projects.
Overall goals of the Tech56 program are to cut specific fuel consumption by 4-7%, achieve a 15-20% reduction in cost of ownership, cut emissions by as much as 40-50% below current International Civil Aviation Organization (ICAO) rules and lower noise by about 20 dB. (cumulative).
Tech56 advanced fan blade developments are aimed at evaluating at least two types of wide-chord, swept-fan blades--a hollow-chord design being tested in a 68-in.-dia. fan and a solid configuration being explored in a 61-in.-dia. fan.
Tests of the 68-in.-dia. fan mounted on a CFM56-5C are scheduled to get underway at Snecma's facilities in Villaroche, France, in the middle of the year. Their purpose is to evaluate fan performance and aeromechanics. Once those trials are completed, the engine will travel to General Electric's Peebles, Ohio, facility in August for crosswind and acoustic testing. Limited performance trials also will be run.
Evaluations of the 61-in.-dia. fan are already complete, having wrapped up in early 2000. Bird shots and blade-out tests were conducted in spin pit facilities at Snecma in late 1999; and in early 2000, a CFM56-7 was fitted with the fan to gauge fan performance and evaluate aeromechanics. The powerplant also underwent crosswind and acoustic testing at Peebles early last year.
TECH56 HIGH-PRESSURE compressor work is centered on a six-stage, high-performance unit that was designed using three-dimensional aerodynamics codes. As a result, it features forward-swept rotors as well as bowed and swept stators. To help reduce maintenance costs, improve durability and lower parts counts, the unit's first two rows employ integrally bladed disk construction.
Overall design objectives for the new compressor were to significantly cut parts count and boost performance while reducing compression stages. According to test results, CFMI has gone a long way toward meeting these goals. At GE's Lynn, Mass., facility a year ago, the new six-stage compressor demonstrated a pressure ratio of about 15:1, significantly better than the current production unit, which achieves one of nearly 11:1 over nine stages. The new unit also has just 968 airfoils, hundreds fewer than the 1,518 used in today's production compressor.
Also demonstrated in the Lynn tests was a superior high-speed stall performance, which was considered the greatest risk in developing the new compressor, Ron Klapproth said. He is manager of Tech56 engineering. In fact, the new compressor exhibited a stall margin 24% above current CFMI products.
Operability also was exceptional. "Since the compressor relies on high stage loading, we were concerned that air distortions could present problems. When running the compressor behind a variety of distortion screens, though, we encountered no problems," Klapproth said.
One issue that did arise, however, was component efficiency. "It's not as good as that in the current product line," he said, so CFMI is proceeding with plans to evaluate a new build of the compressor in May. "The efficiency shortfall was not unexpected because our design philosophy called for going after operability first, then focusing on efficiency. It's just easier to do that," he explained.
To address the performance issue, CFMI is adding changes to the compressor blades, tailoring them using the very best, and most recent, design codes the company has at its disposal. Design of this "build 2" compressor is complete, and it should begin testing at Lynn in May. Trials are expected to last for a couple of months.
CFMI COMBUSTOR IMPROVEMENTS are focused on the company's twin annular pre-swirl (TAPS) combustor, which uses micro-laminate technology in the fuel nozzle to achieve significant emissions reductions. In mid-2000, full annular rig tests of the concept were run at GE's Evendale, Ohio, facilities to examine liner temperatures--a measure of combustor durability--and to optimize fueling modes, ensuring a smooth transition between the combustor's zones.
Initial full engine tests aimed at evaluating the TAPS design in a CFM56 demonstrator concluded last month, after beginning in December. The tests at Evendale examined emissions, control optimization and operability. That same engine, a CFM56-7, is now running at Site 4D at Peebles.
On Mar. 12, this Aviation Week & Space Technology editor observed the most recent tests with the engine. Those trials were aimed at demonstrating the combustor's stability during hail ingestion. About 600 lb. of ice cut into 1/2-in.-dia. balls was successfully ingested and passed by the engine in about 30 sec. on that date with the powerplant running at low speed. According to test engineers, sustaining engine power at low speed during hail ingestion is no mean feat. In fact, flame-out used to be a common occurrence when this weather phenomena was encountered. To date, the powerplant has ingested some 5-6 tons of ice, and before hail testing ends in about three weeks, the engine will have passed about 20 tons.
Once hail trials are complete, the engine will be inspected and then participate in endurance tests that probably will begin in April. Acoustics, operability and controls tests of the TAPS combustor in the CFM56-7 demonstrator also are scheduled and should conclude by midyear.
Later this year, engineers will conduct a new round of TAPS trials after analyzing test data and optimizing the design. The updated TAPS combustor, again fitted into a CFM56-7 demonstrator, should be back in test by year-end.
"WE EXPECT TO REPEAT most of the tests conducted with the baseline 7 engine to refine what we've done. Based on results so far, we really don't expect any significant changes in the TAPS design," Klapproth said. He added that the combustor has already shown that it can cut oxides of nitrogen emissions to levels that are some 65% below the rules adopted by ICAO in 1996.
Brush seal technology is another innovation being pursued under Tech56, and a set of the seals isbeing evaluated for endurance and durability in a CFM56-5Bnow running at Peebles. The seals are replacing conventional labyrinth seals located at the engine's compressor discharge and in its high-pressure turbine. The seal tests began earlier this month and should continue for 60-90 days.
Klapproth said the metallic wire brush seals offer superior performance, and they retain that performance because they can flex during engine imbalances and adjust to accommodate flight maneuvers. Conventional seals tend to chew into their honeycomb rub areas during similar maneuvers, resulting in seal deterioration. In fact, earlier tests demonstrated that the brush seals reduce leakages some 40% when compared with conventional seals.
CFMI conducted full-scale rig tests with the brush seals between late 1999 and the third quarter of last year in Samara, Russia. "We ran the tests there because the Russians had the only facility capable of supporting them," Klapproth said. Subscale rig tests that examined a number of seal designs and configurations also took place at the same time in the U.K., he added.
If the current tests at Peebles are successful, "we'll consider the seals mature," Klapproth said. If unsuccessful, "we'll decide at that time what our next step will be."
ALSO IMPORTANT TO THE TECH56 effort are advanced high- and low-pressure turbine technologies. High-pressure turbine tests have nearly concluded and, according to Klapproth, CFMI considers Tech56's high-pressure turbine advancements to be mature following nearly 70 hr. of rig testing conducted at Evendale last March and April.
Compared with the current CFM56 high-pressure turbine design, the new unit has 10% fewer airfoils, better efficiency and 15% higher loading. The new high turbine also has demonstrated a 22% reduction in blade cooling flow and a 50% reduction in the strength of its trailing-edge shocks.
Despite its "mature" classification, CFMI engineers still plan to tinker with the current high-pressure turbine design and expect to rig test another blade that incorporates the latest improvements available by using the most up-to-date computational fluid dynamics codes.
Tests of that third-generation blade, which engineers hope will further reduce trailing-edge shocks, are scheduled to begin in midyear. For these evaluations, the high-pressure turbine will be installed in GE's unique back-to-back, dual-spool facility. This rig allows researchers to run high- and low-pressure turbines literally "back-to-back" so that interactions between the two can be explored.
CFMI already has investigated two versions of an advanced, counterrotating (relative to the high turbine) low-pressure turbine; and the latest concept, appropriately designated design 3, will begin a month-long set of evaluations in April. The tests will be run in the dual-spool rig at Evendale, with design 3 running close-coupled to the Tech56 advanced high-pressure turbine. This new low-pressure turbine design will parallel the second Tech56 LPT design. But the former offers the added benefit of 10% fewer airfoils.
ACCORDING TO KLAPPROTH, the first LPT design was run in the dual-spool rig in the third quarter of last year and was close-coupled with the Tech56 advanced high-pressure turbine. During follow-up tests, this version of the low pressure turbine also was run by itself in the rig. This initial design had about 15% fewer airfoils compared with the current CFM low-pressure turbine. More importantly, this first design beat the program's projected design point efficiency goal by about 1%.
The second LPT design paralleled that of the first, but with one important exception--a transition duct was added to the space between the high- and low-pressure turbines. Once testing began late last year, it was clear this design also offered an efficiency improvement. In fact, the efficiency of the second design exceeded that of the first "by one-quarter to one-half percent," Klapproth said.
Once design 3 low-pressure turbine tests are over, CFMI engineers will consider the entire Tech56 turbine effort complete, declare the technology mature and pronounce it ready to move into product design--when it's needed, Klapproth said.
Copyright March 19, 2001 The McGraw-Hill Companies
