Application of High Performance Computing for Simulating Cycle-to-Cycle Variation in Dual-Fuel Combustion Engines

Author(s):  
Ravichandra S. Jupudi ◽  
Charles E.A. Finney ◽  
Roy Primus ◽  
Sameera Wijeyakulasuriya ◽  
Adam E. Klingbeil ◽  
...  
2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Sreenivasa Rao Gubba ◽  
Ravichandra S. Jupudi ◽  
Shyam Sundar Pasunurthi ◽  
Sameera D. Wijeyakulasuriya ◽  
Roy J. Primus ◽  
...  

In an earlier publication (Jupudi et al., 2016, “Application of High Performance Computing for Simulating Cycle-to-Cycle Variation in Dual-Fuel Combustion Engines,” SAE Paper No. 2016-01-0798), the authors compared numerical predictions of the mean cylinder pressure of diesel and dual-fuel combustion, to that of measured pressure data from a medium-speed, large-bore engine. In these earlier comparisons, measured data from a flush-mounted in-cylinder pressure transducer showed notable and repeatable pressure oscillations which were not evident in the mean cylinder pressure predictions from computational fluid dynamics (CFD). In this paper, the authors present a methodology for predicting and reporting the local cylinder pressure consistent with that of a measurement location. Such predictions for large-bore, medium-speed engine operation demonstrate pressure oscillations in accordance with those measured. The temporal occurrences of notable pressure oscillations were during the start of combustion and around the time of maximum cylinder pressure. With appropriate resolutions in time steps and mesh sizes, the local cell static pressure predicted for the transducer location showed oscillations in both diesel and dual-fuel combustion modes which agreed with those observed in the experimental data. Fast Fourier transform (FFT) analysis on both experimental and calculated pressure traces revealed that the CFD predictions successfully captured both the amplitude and frequency range of the oscillations. Resolving propagating pressure waves with the smaller time steps and grid sizes necessary to achieve these results required a significant increase in computer resources.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3734
Author(s):  
Javier Monsalve-Serrano ◽  
Giacomo Belgiorno ◽  
Gabriele Di Blasio ◽  
María Guzmán-Mendoza

Notwithstanding the policies that move towards electrified powertrains, the transportation sector mainly employs internal combustion engines as the primary propulsion system. In this regard, for medium- to heavy-duty applications, as well as for on- and off-road applications, diesel engines are preferred because of the better efficiency, lower CO2, and greater robustness compared to spark-ignition engines. Due to its use at a large scale, the internal combustion engines as a source of energy depletion and pollutant emissions must further improved. In this sense, the adoption of alternative combustion concepts using cleaner fuels than diesel (e.g., natural gas, ethanol and methanol) presents a viable solution for improving the efficiency and emissions of the future powertrains. Particularly, the methane–diesel dual-fuel concept represents a possible solution for compression ignition engines because the use of the low-carbon methane fuel, a main constituent of natural gas, as primary fuel significantly reduces the CO2 emissions compared to conventional liquid fuels. Nonetheless, other issues concerning higher total hydrocarbon (THC) and CO emissions, mainly at low load conditions, are found. To minimize this issue, this research paper evaluates, through a new and alternative approach, the effects of different engine control parameters, such as rail pressure, pilot quantity, start of injection and premixed ratio in terms of efficiency and emissions, and compared to the conventional diesel combustion mode. Indeed, for a deeper understanding of the results, a 1-Dimensional spray model is used to model the air-fuel mixing phenomenon in response to the variations of the calibration parameters that condition the subsequent dual-fuel combustion evolution. Specific variation settings, in terms of premixed ratio, injection pressure, pilot quantity and combustion phasing are proposed for further efficiency improvements.


Author(s):  
Adam Klingbeil ◽  
Seunghyuck Hong ◽  
Roy J. Primus

Experiments were conducted on a large bore, medium speed, single cylinder, diesel engine to investigate operation with substitution ratio of natural gas varying from 0 to 93% by energy. As reported in a previous publication [1], these data were used to validate an analytical methodology for predicting performance and emissions under a broad spectrum of energy substitution ratios. For this paper, these experimental data are further analyzed to better understand the performance and combustion behavior under natural gas substitution ratios of 0%, 60% and 93%. These results show that by transitioning from diesel to 60% dual-fuel (60% NG substitution ratio), an improvement in the NOx-efficiency trade-off was observed that represented a ∼3% improvement in efficiency at constant NOx. Further, the transition from 60% dual-fuel to 93% dual-fuel (93% NG substitution ratio) resulted in additional efficiency improvement with a simultaneous reduction in NOx emissions. The data suggest that this improvement can be attributed to the premixed nature of the high substitution ratio. Furthermore, the results show that high cycle-to-cycle variation was observed for the 93% dual-fuel combustion tests. Further analysis, along with diesel injection rate measurements, show that the observed extreme sensitivity of the combustion event can be attributed to critical parameters such as diesel fuel quantity and injection timing. Results suggest a better understanding of the relative importance of combustion system components and operating conditions in controlling cycle-to-cycle variation of combustion process.


MRS Bulletin ◽  
1997 ◽  
Vol 22 (10) ◽  
pp. 5-6
Author(s):  
Horst D. Simon

Recent events in the high-performance computing industry have concerned scientists and the general public regarding a crisis or a lack of leadership in the field. That concern is understandable considering the industry's history from 1993 to 1996. Cray Research, the historic leader in supercomputing technology, was unable to survive financially as an independent company and was acquired by Silicon Graphics. Two ambitious new companies that introduced new technologies in the late 1980s and early 1990s—Thinking Machines and Kendall Square Research—were commercial failures and went out of business. And Intel, which introduced its Paragon supercomputer in 1994, discontinued production only two years later.During the same time frame, scientists who had finished the laborious task of writing scientific codes to run on vector parallel supercomputers learned that those codes would have to be rewritten if they were to run on the next-generation, highly parallel architecture. Scientists who are not yet involved in high-performance computing are understandably hesitant about committing their time and energy to such an apparently unstable enterprise.However, beneath the commercial chaos of the last several years, a technological revolution has been occurring. The good news is that the revolution is over, leading to five to ten years of predictable stability, steady improvements in system performance, and increased productivity for scientific applications. It is time for scientists who were sitting on the fence to jump in and reap the benefits of the new technology.


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