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Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constant

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

《能源前沿(英文)》 2019年 第13卷 第3期   页码 483-493 doi: 10.1007/s11708-019-0631-1

摘要: Liquefied natural gas (LNG), mainly composed of methane, is in progress to substitute diesel fuel in heavy-duty marine engine for practical, economic, and environmental considerations. However, natural gas is relatively difficult to be ignited in a large bore combustion chamber. A combustion enhancement technique called pre-chamber turbulent jet ignition (TJI) can permit combustion and flame propagation in a large-bore volume. To investigate the effect of air-fuel equivalence ratio and pre-mixed pressure on pre-chamber TJI of methane/air mixtures with multiple orifices in a large bore volume, experimental tests and computational simulations were implemented to study the discharge of hot turbulent jets from six orifices of the pre-chamber. Different initial pressures and air-fuel equivalence ratios were considered to analyze the characteristics of TJI. The asymmetry of the turbulent jet actuated from six different orifices were found due to the asymmetric orientation of the spark plug, resulting in the inhomogeneous distribution of combustion in the constant volume chamber, which should be considered seriously in the marine engine design. Besides, as the premixed pressure increases, it has more effect on the flame propagation and plays a more important role, as it further increases.

关键词: marine engine     natural gas     methane     turbulent jet ignition (TJI)     pre-chamber    

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

《能源前沿(英文)》 2021年 第15卷 第2期   页码 396-404 doi: 10.1007/s11708-020-0715-y

摘要: Jet fuel is widely used in air transportation, and sometimes for special vehicles in ground transportation. In the latter case, fuel spray auto-ignition behavior is an important index for engine operation reliability. Surrogate fuel is usually used for fundamental combustion study due to the complex composition of practical fuels. As for jet fuels, two-component or three-component surrogate is usually selected to emulate practical fuels. The spray auto-ignition characteristics of RP-3 jet fuel and its three surrogates, the 70% mol -decane/30% mol 1,2,4-trimethylbenzene blend (Surrogate 1), the 51% mol -decane/49% mol 1, 2, 4-trimethylbenzene blend (Surrogate 2), and the 49.8% mol -dodecane/21.6% mol -cetane/28.6% mol toluene blend (Surrogate 3) were studied in a heated constant volume combustion chamber. Surrogate 1 and Surrogate 2 possess the same components, but their blending percentages are different, as the two surrogates were designed to capture the H/C ratio (Surrogate 1) and DCN (Surrogate 2) of RP-3 jet fuel, respectively. Surrogate 3 could emulate more physiochemical properties of RP-3 jet fuel, including molecular weight, H/C ratio and DCN. Experimental results indicate that Surrogate 1 overestimates the auto-ignition propensity of RP-3 jet fuel, whereas Surrogates 2 and 3 show quite similar auto-ignition propensity with RP-3 jet fuel. Therefore, to capture the spray auto-ignition behaviors, DCN is the most important parameter to match when designing the surrogate formulation. However, as the ambient temperature changes, the surrogates matching DCN may still show some differences from the RP-3 jet fuel, e.g., the first-stage heat release influenced by low-temperature chemistry.

关键词: RP-3 jet fuel     surrogate     spray auto-ignition     constant volume combustion chamber    

Influence of nozzle height to width ratio on ignition and NO

Liutao SUN, Yonghong YAN, Rui SUN, Zhengkang PENG, Chunli XING, Jiangquan WU

《能源前沿(英文)》 2021年 第15卷 第2期   页码 431-448 doi: 10.1007/s11708-021-0726-3

摘要: To improve the ignition behavior and to reduce the high NO emissions of blended pulverized fuels (PF) of semicoke (SC), large-scale experiments were conducted in a 300 kW fired furnace at various nozzle settings, i.e., ratios (denoted by / ) of the height of the rectangular burner nozzle to its width of 1.65, 2.32, and 3.22. The combustion tests indicate that the flame stability, ignition performance, and fuel burnout ratio were significantly improved at a nozzle setting of / = 2.32. The smaller / delayed ignition and caused the flame to concentrate excessively on the axis of the furnace, while the larger / easily caused the deflection of the pulverized coal flame, and a high-temperature flame zone emerged close to the furnace wall. NO emissions at the outlet of the primary zone decreased from 447 to 354 mg/m (O = 6%), and the ignition distance decreased from 420 to 246 mm when the / varied from 1.65 to 3.22. Furthermore, the ratio (denoted by / ) of the strong reduction zone area to the combustion reaction zone area was defined experimentally by the CO concentration to evaluate the reduction zone. The / rose monotonously, but its restraining effects on NO formation decreased as / increased. The results suggested that in a test furnace, regulating the nozzle / conditions sharply reduces NO emissions and improves the combustion efficiency of SC blends possessing an appropriate jet rigidity.

关键词: rectangular jet burner     nozzle height to width ratio     ignition characteristics     pyrolyzed semicoke (SC) and bituminous blend     NOx formation    

Experimental study of humid air reverse diffusion combustion in a turbulent flow field

GE Bing, ZANG Shusheng, GU Xin

《能源前沿(英文)》 2007年 第1卷 第4期   页码 428-434 doi: 10.1007/s11708-007-0062-6

摘要: Experiments were performed to investigate the differences between the propane/air turbulent diffusion reactive flows past bluff-body and the propane/humid air turbulent diffusion reactive flows in the same conditions. The velocity

关键词: propane/humid     propane/air turbulent     bluff-body     turbulent diffusion    

Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 198-204 doi: 10.1007/s11708-009-0054-5

摘要: A spatial linear instability analysis is conducted on an annular viscous liquid jet injected into compressible gases and a three-dimensional model of the jet is developed. The model takes into account differences between the velocities, densities of the gases inside and outside of the liquid jet. Theoretical analysis reveals that there exist 9 dimensionless parameters controlling the instability of the liquid jet. Numerical computations reveal some basic characteristics in the breakup and atomization process of the liquid jet as well as influences of these relevant parameters. Major observations and findings of this study are as follows. The Mach number plays a destabilizing role and the inner Mach number has a greater effect on the jet instability than the outer Mach number. The Reynolds number always tends to promote the instabilities of the liquid jet, but its influence is very limited. The Weber number and the gas-to-liquid density ratio also have unstable effects and can improve the atomization of liquid jets. Furthermore, the effects of the Weber number and gas-to-liquid density ratio on the maximum growth rates of axisymmetric and non-axisymmetric disturbances and corresponding dominant wave numbers are manifested in a linear way, while that of the Mach number is non-linear. The effect of Reynolds on the maximum growth rates is non-linear, but the dominant wavenumber is almost not affected by the Reynolds number.

关键词: liquid jet     dominant wave number     compressibility     instability    

An experimental study on ignition of single coal particles at low oxygen concentrations

Wantao YANG, Yang ZHANG, Lilin HU, Junfu LYU, Hai ZHANG

《能源前沿(英文)》 2021年 第15卷 第1期   页码 38-45 doi: 10.1007/s11708-020-0692-1

摘要: An experimental study on the ignition of single coal particles at low oxygen concentrations ( <21%) was conducted using a tube furnace. The surface temperature ( ) and the center temperature ( ) of the coal particles were obtained from the images taken by an infrared camera and thermocouples respectively. The ignition processes were recorded by a high-speed camera at different values and furnace temperatures . Compared with literature experimental data obtained at a high value, the ignition delay time decreases more rapidly as increases at the low region. The responses of and to the variation of are different: decreases while remains nearly constant with increasing at a low value. In addition, is less sensitive to while the ignition temperature is more sensitive to at a low value than in air. Observations of the position of flame front evolution illustrate that the ignition of a coal particle may change from a homogeneous mode to a heterogeneous or combined ignition mode as decreases. At a low value, buoyancy plays a more significant role in sweeping away the released volatiles during the ignition process.

关键词: coal particles     low oxygen concentration     ignition     ignition temperature     ignition modes    

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 432-439 doi: 10.1007/s11708-009-0050-9

摘要: A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4=ch3cho+c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2=ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.

关键词: compression-ignition engine     ignition mechanism     elementary reaction     n-heptane    

Large eddy simulation of turbulent buffet forces in flow induced vibration

XI Zhide, CHENG Bingde, LI Pengzhou

《能源前沿(英文)》 2008年 第2卷 第4期   页码 524-527 doi: 10.1007/s11708-008-0099-x

摘要: The pressure pulse filter and Smagorinsky sub-grid stress model of the Large Eddy Simulation (LES) are introduced. The fluid field in the annular plenum between the pressure vessel and the core barrel of the1:5 model in the second phase of Qinshan Nuclear Power Plant is simulated, and the distribution of the total pressure in the space and time domains is obtained. The results show that the Power Spectrum Density (PSD) of LES from the calculation and the test are in the same quantity order. Thus, the pressure of LES can be a load to stimulate the barrel vibration.

关键词: Spectrum Density     Smagorinsky sub-grid     vibration     calculation     Qinshan Nuclear    

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

《能源前沿(英文)》 2023年 第17卷 第5期   页码 664-677 doi: 10.1007/s11708-021-0787-3

摘要: The combustion characteristics and emission behaviors of RP-3 jet fuel were studied and compared to commercial diesel fuel in a single-cylinder compression ignition (CI) engine. Engine operational parameters, including engine load (0.6, 0.7, and 0.8 MPa indicating the mean effective pressure (IMEP)), the exhaust gas recirculation (EGR) rate (0%, 10%, 20%, and 30%), and the fuel injection timing (−20, −15, −10, and −5 ° crank angle (CA) after top dead center (ATDC)) were adjusted to evaluate the engine performances of RP-3 jet fuel under changed operation conditions. In comparison to diesel fuel, RP-3 jet fuel shows a retarded heat release and lagged combustion phase, which is more obvious under heavy EGR rate conditions. In addition, the higher premixed combustion fraction of RP-3 jet fuel leads to a higher first-stage heat release peak than diesel fuel under all testing conditions. As a result, RP-3 jet fuel features a longer ignition delay (ID) time, a shorter combustion duration (CD), and an earlier CA50 than diesel fuel. The experimental results manifest that RP-3 jet fuel has a slightly lower indicated thermal efficiency (ITE) compared to diesel fuel, but the ITE difference becomes less noticeable under large EGR rate conditions. Compared with diesel fuel, the nitrogen oxides (NOx) emissions of RP-3 jet fuel are higher while its soot emissions are lower. The NOx emissions of RP-3 can be effectively reduced with the increased EGR rate and delayed injection timing.

关键词: RP-3 jet fuel     diesel     engine     combustion     emissions    

Numerical simulation of three-dimensional turbulent flow in multistage axial compressor blade row

JIANG Jian, LIU Bo, WANG Yangang, NAN Xiangyi

《能源前沿(英文)》 2008年 第2卷 第3期   页码 320-325 doi: 10.1007/s11708-008-0041-2

摘要: Numerical simulation of three-dimensional turbulent flow in a multistage axial compressor blade row is conducted. A high resolution, third-order ENN scheme is adopted to catch the shockwave and simulate the turbulent flow correctly,

关键词: simulation     compressor     multistage     third-order     three-dimensional turbulent    

Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

《机械工程前沿(英文)》 2017年 第12卷 第4期   页码 477-489 doi: 10.1007/s11465-017-0461-y

摘要:

Electrohydrodynamic jet (E-Jet) is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication of micro/nano-structures for micro/nano-electromechanical system devices. This technique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.

关键词: electrohydrodynamic jet deposition     electrohydrodynamic jet printing     micro/nano-structures     film    

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

《能源前沿(英文)》 2013年 第7卷 第3期   页码 406-412 doi: 10.1007/s11708-013-0266-6

摘要: To reduce oil consumption during firing-up and partial-load operation, a tiny-oil ignition burner has been recommended. Through reacting-flow experiments performed on a full-scale experimental setup, the influence of different oil flow rates on bituminous coal combustion as well as flow rates without coal feed was analyzed. The ignition burner is identical to that normally used in an 800 MWe utility boiler. Under operating conditions with flow rates of 50, 100, and 150 kg/h, gas temperature distributions were measured in the burner. At the equivalent measuring points at the exits of the first and second combustion chambers, these distributions remained almost unchanged under a constant coal feed rate of 4 t/h. However on the burner centerline, distributions increased slightly with increasing flow rate. Different gas concentrations were measured at the center of the burner exit. For instance, the O concentration at the burner exit varied from 0.01% to 0.31% whereas CO concentrations were more than 10000 ppm. At the same coal feed rate of 4 t/h, burner resistances are 480, 600, and 740 Pa for oil flow rates of 50, 100, and 150 kg/h, respectively.

关键词: ignition     coal     burner     boiler     oil flow rate    

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 384-398 doi: 10.1007/s11705-020-1928-7

摘要: The jet-flow high shear mixer (JF-HSM) is a new type of intensified equipment with special configurations of the rotor and the stator. The mass transfer property and power consumption were studied in the solid-liquid system for a series of JF-HSMs involving different configuration parameters, such as rotor diameter, rotor blade inclination, rotor blade bending direction, stator diameter, and stator bottom opening diameter. The flow characteristics were examined by computational fluid dynamic simulations. Results indicate that the turbulent power consumption of the JF-HSM is affected by the change in rotor blade inclination and stator bottom opening. With the increase in the shear head size and the change in the rotor into a backward-curved blade, the solid-liquid mass transfer rate can be remarkably increased under the same input power. Dimensionless correlations for the mass transfer coefficient and power consumption were obtained to guide the scale-up design and selection of such a new type of equipment to intensify the overall mixing efficiency.

关键词: jet-flow high shear mixer     solid particle dissolution     power consumption characteristics     CFD Simulation    

Numerical simulation of combustion characteristics at different coal concentrations in bituminous coal ignitionin a tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Yiquan XIE, Lingyan ZENG

《能源前沿(英文)》 2013年 第7卷 第2期   页码 255-262 doi: 10.1007/s11708-013-0255-9

摘要: With the objective of producing a full-scale tiny-oil ignition burner, identical to the burner used in an 800 MWe utility boiler, numerical simulations were performed using Fluent 6.3.26 to study the progress of ignition for four coal concentration settings covering sub-operation conditions prevailing during the experiments performed with the burner. The numerical simulations conformed to the experimental results, demonstrating the suitability of the model used in the calculations. Simulations for a coal concentration of 0.40 kg/kg corresponding to a single burner operating at its rated output were also conducted, which indicated that gas temperatures along the burner centerline were high. As gas flowed to the burner nozzle, the high-temperature region expanded, ensuring a successful pulverized-coal ignition. With increasing coal concentration (0.08–0.40 kg/kg), the gas temperature along the burner centerline and at the first and second combustion chamber exits decreased at the equivalent radial points. At the center of the second combustion chamber exit, the O concentrations were almost depleted for the five coal concentrations, while the CO concentrations peaked.

关键词: numerical simulation     tiny-oil ignition burner     pulverized coal     temperature field    

柴油在热壁面上的着火

栗元龙,陆守香,范维澄

《中国工程科学》 2004年 第6卷 第11期   页码 63-65

摘要:

研究了柴油机燃料泄漏后在热壁上的着火,利用统计方法得到着火的临界温度。发现样品燃料的热壁着火温度与自燃点的差值比其它燃料热壁着火的相应值要小得多,而且着火方式也有很大差异。详细解释了泄漏后的液体在热表面上的沸腾蒸发模式,给出了燃料蒸气的质量流率推导公式。

关键词: 热壁面     着火实验     沸腾    

标题 作者 时间 类型 操作

Pre-chamber turbulent jet ignition of methane/air mixtures with multiple orifices in a large bore constant

Xiang LI, Wenzheng ZHANG, Zhong HUANG, Dehao JU, Li HUANG, Mingzhi FENG, Xingcai LU, Zhen HUANG

期刊论文

An experimental study on spray auto-ignition of RP-3 jet fuel and its surrogates

Yaozong DUAN, Wang LIU, Zhen HUANG, Dong HAN

期刊论文

Influence of nozzle height to width ratio on ignition and NO

Liutao SUN, Yonghong YAN, Rui SUN, Zhengkang PENG, Chunli XING, Jiangquan WU

期刊论文

Experimental study of humid air reverse diffusion combustion in a turbulent flow field

GE Bing, ZANG Shusheng, GU Xin

期刊论文

Stability of an annular viscous liquid jet in compressible gases with different properties inside andoutside of the jet

Chunji YAN, Maozhao XIE,

期刊论文

An experimental study on ignition of single coal particles at low oxygen concentrations

Wantao YANG, Yang ZHANG, Lilin HU, Junfu LYU, Hai ZHANG

期刊论文

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

期刊论文

Large eddy simulation of turbulent buffet forces in flow induced vibration

XI Zhide, CHENG Bingde, LI Pengzhou

期刊论文

Combustion and emissions of RP-3 jet fuel and diesel fuel in a single-cylinder diesel engine

期刊论文

Numerical simulation of three-dimensional turbulent flow in multistage axial compressor blade row

JIANG Jian, LIU Bo, WANG Yangang, NAN Xiangyi

期刊论文

Fabrication of micro/nano-structures by electrohydrodynamic jet technique

Dazhi WANG, Xiaojun ZHAO, Yigao LIN, Tongqun REN, Junsheng LIANG, Chong LIU, Liding WANG

期刊论文

Influence of different oil feed rate on bituminous coal ignition in a full-scale tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Xiang ZHANG, Zhichao CHEN

期刊论文

Effects of rotor and stator geometry on dissolution process and power consumption in jet-flow high shear

Lin Yang, Wenpeng Li, Junheng Guo, Wei Li, Baoguo Wang, Minqing Zhang, Jinli Zhang

期刊论文

Numerical simulation of combustion characteristics at different coal concentrations in bituminous coal ignitionin a tiny-oil ignition burner

Chunlong LIU, Qunyi ZHU, Zhengqi LI, Qiudong ZONG, Yiquan XIE, Lingyan ZENG

期刊论文

柴油在热壁面上的着火

栗元龙,陆守香,范维澄

期刊论文