Article
Thermodynamics
Hyung Sub Sim, Noud Maes, Lukas Weiss, Lyle M. Pickett, Scott A. Skeen
Summary: This study investigates the low- and high-temperature ignition and combustion processes in a high-pressure spray flame of n-dodecane using simultaneous PLIF and schlieren imaging. The results show that the formation and propagation of HCHO from lean to rich regions lead to high-temperature ignition events, supporting the identification of a phenomenon dubbed cool-flame wave propagation. High-temperature ignition consumes previously formed HCHO in the jet head, while HCHO formation persists near the flame base in the fuel-rich zone throughout the combustion period.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Hyung Sub Sim, Noud Maes, Lyle M. Pickett, Scott A. Skeen, Julien Manin
Summary: This study investigates the impact of injection pressure and ambient oxygen concentration on the Engine Combustion Network Spray A flame using high-speed PLIF and schlieren imaging techniques. The experimental data obtained provides valuable insights into the spatiotemporal distribution of CH 2 O and PAH, and can be used for detailed evaluation of combustion simulations.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Minggang Wan, Jiajian Zhu, Mingbo Sun, Shu Zheng, Bo Zhou, Yuhui Huang, Hongbo Wang, Yao Liu, Ge Wu, Zhenguo Wang
Summary: Conducting CH2O PLIF imaging in scramjets is challenging due to strong flame emissions (FEs). To overcome this challenge, a CH2O PLIF imaging strategy utilizing 353.06 nm excitation and capturing two frames with a time delay was proposed. The strategy reduced FE interference and improved the signal-to-background ratio from 1-2 to 10, enabling CH2O PLIF imaging in scramjets.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Fabien Tagliante, Tuan M. Nguyen, Meghna P. Dhanji, Hyung Sub Sim, Lyle M. Pickett, Julien Manin, Goutham Kukkadapu, Russell Whitesides, Kevin Wan
Summary: This work investigates the low-and high-temperature ignition and combustion processes, applied to the Engine Combustion Network Spray A flame, combining advanced optical diagnostics and large-eddy simulations (LES). Simultaneous high-speed formaldehyde (CH2O) planar laser-induced fluorescence (PLIF) and line-of-sight OH * chemiluminescence imaging were used to measure the low-and high -temperature flame, during ignition as well as during quasi-steady combustion.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Yejun Wang, Ayush Jain, Christian Schweizer, Waruna D. Kulatilaka
Summary: Comparison of flame structure, PAH, and soot formation characteristics of commercial diesel and a diesel surrogate was conducted using optical diagnostics. The study found that diesel produced approximately 1.5 times more soot than the diesel surrogate, indicating the need for more appropriate diesel surrogates.
COMBUSTION AND FLAME
(2021)
Article
Engineering, Mechanical
Arman Rostampour, Mohammad Hassan Shojaeefard, Gholam Reza Molaeimanesh
Summary: Spray simulation is crucial for engine simulations, and the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) model is commonly used. This study investigates the effects of KH-RT model constants, LES, and RANS turbulence models on spray penetration length and shape of diesel spray contour. The results show that both LES and RANS turbulence models, along with the KH-RT model, accurately predict the spray penetration length. However, the RANS model fails to accurately capture the soft edges of the spray contour.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Chenghan Sun, Zhongjie Shi, Yikai Li, Yue Lou, Gaoran Wei, Ziming Yang
Summary: A four-component diesel surrogate fuel was developed using n-butylcyclohexane as the representative of alkylcyclohexanes with a long alkyl chain. The surrogate fuel can reproduce the physicochemical characteristics of real diesel, and a reduced mechanism and skeletal mechanism were developed and validated.
Article
Optics
Xiang Li, Qingchun Lei, Wei Bao, Xuesong Li, Wei Fan
Summary: This Letter presents the first demonstration of a high-speed three-dimensional (3D) schlieren technique that combines fiber imaging, Toepler's lens-type schlieren, and computed tomography (CT). The technique captures schlieren images of turbulent flames from seven orientations simultaneously using a single high-speed camera, two xenon lamps, and fiber bundles, with a framerate beyond tens of kHz. The method is flexible, high speed, and low cost, complementing existing techniques. It has been validated on turbulent and laminar premixed flames and used to measure the transient ignition process, obtaining time-resolved 3D fundamental properties of ignition kernels.
Article
Optics
Hao Guo, Wei Zhang, Xiangyu Nie, Xue Dong, Zhiwei Sun, Bo Zhou, Zhenkan Wang, Mattias Richter
Summary: In this paper, a computational imaging method based on deep learning models is proposed to increase the temporal resolution of planar optical measurement in turbulent flames. The method utilizes down-sampled experimental data and trains networks to predict consecutive images of key combustion species. The results show that the convolutional long short-term memory network (CONV-LSTM) provides the best predictions and can generate consecutive images at higher repetition rates.
APPLIED PHYSICS B-LASERS AND OPTICS
(2022)
Article
Chemistry, Physical
Zuo Ni, Quan Dong, Dingwen Wang, Xiyu Yang
Summary: This paper investigates the macroscopic structure and concentration distribution characteristics of a high-pressure gas jet using the schlieren imaging method and laser-induced fluorescence imaging method. The results show that the gas jet penetration and volume correlation equations vary under different injection pressure ratio and gas injection moment. The later stage of the gas jet is divided into four regions, and the length and concentration distribution of these regions are affected by the injection pressure ratio and gas injection moment.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Siba Prasad Choudhury, Ratan Joarder
Summary: In this study, high-speed photography and background oriented schlieren (BOS) techniques were used to investigate the formation of tulip flames in half-open and closed-ends type channels using a premixed mixture of liquefied petroleum gas (LPG) and air. The results showed that the classical tulip flame shape was observed only in the closed channel. Refractive index and flow density were calculated numerically, and pseudo-schlieren images, shadowgrams, and density contours were plotted using the BOS technique.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Allen Parker, C. L. Wanstall, Shawn A. Reggeti, Joshua A. Bittle, Ajay K. Agrawal
Summary: Extensive study is still required on the physical and chemical phenomena that occur during fuel injection, entrainment, fuel-air mixing, cool-flame and ignition reaction, and combustion in diesel sprays. High-speed rainbow schlieren deflectometry and OH* chemiluminescence are used to image these processes in a transient diesel-like flame, with multiple injections conducted in quick succession to gather a statistically relevant dataset for analysis. The study reveals structural features of the spray regions, quantifies jet penetration and spreading rates, and examines various combustion processes such as cool flame behavior, ignition, flame propagation, and stabilization.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Review
Green & Sustainable Science & Technology
Djati Wibowo Djamari, Muhammad Idris, Permana Andi Paristiawan, Muhammad Mujtaba Abbas, Olusegun David Samuel, Manzoore Elahi M. Soudagar, Safarudin Gazali Herawan, Davannendran Chandran, Abdulfatah Abdu Yusuf, Hitesh Panchal, Ibham Veza
Summary: Research and development in the internal combustion engine have been growing, and diesel engines have advantages in efficiency, power output, and reliability. Although observing diesel spray is complex due to its high-speed, high-pressure, and high-temperature conditions, some mechanisms have been explained and suggestions have been made. This paper comprehensively reviews the current status of theoretical diesel spray and modeling.
Article
Energy & Fuels
Long Liu, Yan Peng, Li Huang, Changfu Han, Xiuzhen Ma
Summary: This paper investigates the influence of spray impingement on the mixing process and optimizes the stochastic combustion model to account for this effect. The results show that spray impingement significantly enhances the fuel-air mixing rate, resulting in a leaner and more homogenous mixture and optimizing the combustion process.
Article
Engineering, Multidisciplinary
HeCong Liu, JianQing Huang, Lei Li, WeiWei Cai
Summary: This research focuses on developing a cost-effective BOST system for the simultaneous retrieval of refractive index, density, and temperature distributions for asymmetric flames. Numerical and experimental demonstrations show that the implemented BOST can successfully reconstruct the three-dimensional temperature distribution with satisfactory accuracy.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2021)
