Advanced simulation on Titan contributes to breakthrough efficiency gains
In 2017, US-based General Electric (GE) delivered its newest heavy-duty gas turbine, the 7HA.02, to two power plants in Texas. The installations marked a milestone in natural gas–derived electricity generation, setting new marks in efficiency and emissions for utility-scale turbomachinery.
A key ingredient in GE’s successful recipe for this breakthrough technology was the ability to conduct critical modeling and simulation on the Titan supercomputer, a leadership-class system managed by the Oak Ridge Leadership Computing Facility (OLCF), a US Department of Energy (DOE) Office of Science User Facility at DOE’s Oak Ridge National Laboratory.
In 2015, GE researchers—in collaboration with software company Cascade Technologies—used Titan to investigate an unexpected combustion instability that had been revealed during tests of a GE gas turbine 1 year earlier. Although GE had determined that instability would not affect gas turbine performance, the company wanted to understand its cause and whether it would manifest in a new gas turbine design.
A concern was that the instability might be excited and increase amplitude with axial fuel staging (AFS). Developed with DOE support, AFS enabled turbine operation at higher temperatures with lower emissions. It accomplished this by introducing a second fuel injection stage into the turbine’s combustion system at a point later than the current industry standard.
“To help meet our deadlines, we wanted to see if we could reproduce the instability numerically,” said Joe Citeno, GE Power combustion engineering manager. “But we didn’t have a predictive model or the internal computational horsepower needed to run it.”
The Cascade team, in partnership with GE, created a groundbreaking high-fidelity model on Titan to examine combustion physics at unprecedented resolution. The team successfully reproduced the instability numerically on Titan and then predicted it would not affect performance in the new 7HA.02 gas turbine design. Physical experiments later confirmed the prediction, validating that the combined GE–Cascade team had created a powerful advanced modeling approach that can predict a range of combustion performance variables for GE’s gas turbine combustor designs, including air-fuel mixing, flame stability, emissions, and exit temperatures.
“The availability of the Titan supercomputer enabled a breakthrough that otherwise would have remained unrealized,” Citeno said. The new 7HA.02 gas turbine was put into production on schedule, and the first systems were successfully installed in Texas in the spring of 2017.
Now, GE is busy fulfilling orders for this new turbine, which can achieve an overall efficiency of more than 62 percent in a combined-cycle plant; it is projected to exceed world-record efficiency marks set by GE’s 9HA turbine model. “For our customers, that means lower fuel consumption and reduced cost per megawatt,” Citeno said.
The 7HA.02 installations are more than 2 percent higher than previous 7F-class gas turbines in combined cycle efficiency. This improvement may seem small, but even a small change can produce an enormous impact. For example, just a 1 percent efficiency gain applied across the entire US combined-cycle fleet would save an estimated $11 billion or more in fuel over the next 20 years.
At the Texas plants, the new turbines can respond quickly to fluctuating power demands, filling a critical role in the state’s energy portfolio. During periods of high demand, the plants can provide power for more than 2 million homes.
Building on its simulation success and still working with Cascade, GE continues to use advanced software and its own high-performance computers to evaluate new product designs and test the limits of modern engineering—meaning high-performance computing will likely play a major role in the next leap forward in combustion systems.
“It’s enabling us to be more confident in the moves we make to increase efficiency and product flexibility,” Citeno said.
The OLCF is a DOE Office of Science User Facility located at Oak Ridge National Laboratory. Oak Ridge National Laboratory is supported by the US Department of Energy’s Office of Science. The single largest supporter of basic research in the physical sciences in the United States, the Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
"Mfano wa ""Titan"" ni turbine ya gesi ya General Electric, ambayo ilitengenezwa na kampuni ya umeme ya Amerika, ambayo ilitoa turbine yake mpya ya gesi ya 7HA02 kwa mitambo miwili ya umeme huko Texas." Vifaa hivyo vilionyesha hatua muhimu katika uzalishaji wa umeme unaotokana na gesi ya asili, na kuweka alama mpya katika ufanisi na uzalishaji kwa mashine za turbomachinery za kiwango cha huduma. "Kifaa muhimu katika kichocheo cha mafanikio ya GE kwa teknolojia hii ya mafanikio ilikuwa uwezo wa kufanya ""mfano muhimu"" na ""mfano"" kwenye kompyuta kubwa ya Titan, mfumo wa uongozi wa darasa unaosimamiwa na Oak Ridge Leadership Computing Facility (OLCF), Ofisi ya Ujenzi ya Idara ya Nishati ya Marekani (DOE) katika Maabara ya Kitaifa ya Oak Ridge." Katika 2015, watafiti wa GE, kwa kushirikiana na kampuni ya programu ya Cascade Technologies, walitumia Titan kuchunguza kutoelewana kwa mwako ambao ulifunuliwa wakati wa majaribio ya turbine ya gesi ya GE mwaka mmoja mapema. Ingawa GE ilikuwa imeamua kwamba ukosefu wa uthabiti hautaathiri utendaji wa turbine ya gesi, kampuni hiyo ilitaka kuelewa sababu yake na kama itaonekana katika muundo mpya wa turbine ya gesi. Wasiwasi ulikuwa kwamba kutokuwa na utulivu inaweza kuwa msisimko na kuongeza amplitude na axial mafuta staging (AFS). Ilianzishwa na msaada wa DOE, AFS iliwezesha operesheni ya turbine katika joto la juu na uzalishaji wa chini. Ni kukamilika hii kwa kuanzisha hatua ya pili ya mafuta sindano katika turbine ya mfumo wa kuchoma katika hatua ya baadaye kuliko kiwango cha sasa sekta. "Kusaidia kukidhi tarehe zetu za mwisho, tulitaka kuona kama tunaweza kuzalisha ukosefu wa utulivu kwa idadi", alisema Joe Citeno, meneja wa uhandisi wa mwako wa GE Power. """Lakini hatukuwa na mfano wa utabiri au nguvu ya ndani ya hesabu inayohitajika kuendesha, timu ya Cascade, kwa kushirikiana na GE, iliunda mfano wa uaminifu wa juu kwenye Titan kuchunguza fizikia ya mwako kwa azimio lisilo la kawaida." Timu hiyo ilifanikiwa kuiga kutoelewana kwa idadi kwenye Titan na kisha ikitabiri haitaathiri utendaji katika muundo mpya wa turbine ya gesi ya 7HA-2. Majaribio ya fizikia baadaye yalithibitisha utabiri huo, ikithibitisha kwamba timu ya pamoja ya GE Cascade iliunda mbinu ya hali ya juu ya kuunda ambayo inaweza kutabiri safu ya vigezo vya utendaji wa kuchoma kwa miundo ya turbine ya gesi ya GE, pamoja na mchanganyiko wa hewa na mafuta, utulivu wa moto, uzalishaji, na joto la kutoka. "Upatikanaji wa kompyuta kubwa ya Titan uliruhusu mafanikio ambayo vinginevyo yangebaki yasiyotimizwa", Citeno alisema. Turbine mpya ya gesi ya 7HA02 ilianzishwa kwa muda, na mifumo ya kwanza iliwekwa kwa mafanikio huko Texas katika majira ya kuchipua ya 2017. "Geo sasa ni busy kutimiza maagizo kwa ajili ya turbine hii mpya, ambayo inaweza kufikia ufanisi wa jumla ya zaidi ya 62% katika kiwanda cha mzunguko mchanganyiko; ni projected kupita alama za ufanisi wa rekodi ya dunia iliyowekwa na GE ya ""9HA"" turbine mfano." "Kwa wateja wetu, hiyo inamaanisha matumizi ya chini ya mafuta na gharama iliyopunguzwa kwa megawatt", Citeno alisema. 7H2T ni moja ya turbines ya kwanza ya aina ya 7H2T ambayo imepatikana katika soko la kimataifa. Mabadiliko hayo yanaweza kuonekana kuwa madogo, lakini hata mabadiliko madogo yanaweza kuwa na matokeo makubwa. Kwa mfano, tu 1% ufanisi faida kutumika katika Marekani nzima pamoja-mzunguko meli, ingekuwa kuokoa takriban $ 11 bilioni au zaidi katika mafuta katika miaka ijayo 20. Katika mitambo ya Texas, turbines mpya inaweza kujibu haraka kwa mahitaji ya nguvu fluctuating, kujaza jukumu muhimu katika mfululizo wa nishati ya serikali. Katika kipindi cha mahitaji ya juu, mitambo inaweza kutoa umeme kwa nyumba zaidi ya milioni mbili. Kutegemea mafanikio yake ya simulation na bado kufanya kazi na Cascade, GE inaendelea kutumia programu ya juu na kompyuta zake za utendaji wa juu kutathmini miundo mpya ya bidhaa na kupima mipaka ya uhandisi wa kisasa, ikimaanisha kompyuta ya utendaji wa juu inaweza kucheza jukumu kubwa katika leap ijayo mbele katika mifumo ya mwako. "Inatuwezesha kuwa na ujasiri zaidi katika hatua tunazofanya ili kuongeza ufanisi na kubadilika kwa bidhaa", Citeno alisema. OLCF ni ofisi ya DOE ya Kituo cha Mtumiaji wa Sayansi iliyoko Oak Ridge National Laboratory. Oak Ridge National Laboratory inasaidiwa na Idara ya Marekani ya Nishati ya Ofisi ya Sayansi. Ofisi ya Sayansi, msaidizi mkubwa wa utafiti wa msingi katika sayansi ya fizikia nchini Marekani, inafanya kazi ili kukabiliana na baadhi ya changamoto muhimu zaidi za wakati wetu. Kwa habari zaidi, tafadhali tembelea science.energy.gov.