ONE-DIMENSIONAL MODEL ON FUEL PENETRATION IN DIESEL SPRAYS WITH GAS FLOW

M. XU,Y. C. SUN,Y. CUI,K. Y. DENG,L. SHI 한국자동차공학회 2016 International journal of automotive technology Vol.17 No.1

In diesel engine, spray penetration is usually changed by in-cylinder gas flow. Accurate prediction on diesel spray with gas flow is important to the optimal design of diesel fuel injection system. This paper presents a theory investigation focusing on the penetration of diesel spray with gas flow. In order to understand the effect of gas flow on the penetration of diesel spray, a one-dimensional spray model is developed from an idealized diesel spray, which is able to predict the spray behavior under different gas flow conditions. The ambient gas flow is simplified as ideal flow that has only constant flow velocity along x-axial and y-axial directions of spray. The x-axial and y-axial directions are respectively defined as along and vertical spray directions. The main assumption is that the y-axial direction gas flow has no effect on the penetration of spray along x-axial direction. The principles of conservation of mass and momentum are used in the derivation. Momentum of in-cylinder air flow is also taken into consideration. Validation of the model at stable condition is achieved by comparing model predictions with experimental measurements of diesel spray without gas flow from Naber's experiments. Furthermore, CFD simulations on penetration of diesel spray with gas flow were performed with the commercial code AVL-fire. The onedimensional model is validated by the penetration results with gas flow from CFD calculation. Results show that a reasonable estimation of the spray evolution can be obtained for both with and without ambient gas flow conditions.

EXPERIMENTAL STUDY ON REGENERATING FOULED EGR COOLER BY NTPI TECHNOLOGY

Y. Y. CHEN,Y. X. CAI,X. H. LI,Y. X. SHI,Y. ZHENG 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.2

In order to investigate the regeneration effect of non-thermal plasma injection (NTPI) technology on fouled exhaust gas recirculation (EGR) cooler, NTPI regeneration apparatus and EGR cooler performance test system were built up. Results showed that non-thermal plasma (NTP) could peel off the deposit layer and improve the heat exchange performance effectively. The carbon removal energy efficiency of this NTPI regeneration setup was 22.46 g/kWh and the O3 utilization ratio was 96.50%. To get a deeper understanding of the regeneration effect, thermo-gravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were introduced to investigate the variation of deposit layer’s physical and chemical characteristics before and after regeneration. Results showed that the content of soluble organic fraction (SOF) in deposit specimen decreased obviously, mainly because the carbonyls were effectively removed by NTP. Moreover, soot in deposit specimen was successfully activated by NTP.

High-performance green phosphorescent top-emitting organic light-emitting diodes based on FDTD optical simulation

Shi, X.,Wang, J.,Liu, J.,Huang, S.,Wu, X.,Chen, C.,Lu, J.,Su, Y.,Zheng, Y.,Kim, W.Y.,He, G. Elsevier Science 2014 Organic electronics Vol.15 No.4

We have successfully applied finite-difference time-domain (FDTD) method in top-emitting organic light-emitting diodes (TOLEDs) for structure optimization, demonstrating good agreement with experimental data. A mixed host with both hole transport and electron transport materials is employed for the green phosphorescent emitter to avoid charge accumulation and broaden the recombination zone. The resulting TOLEDs exhibit ultra-high efficiencies, low current efficiency roll-off, and a highly saturated color, as well as hardly detectable spectrum shift with viewing angles. In particular, a current efficiency of 127.0cd/A at a luminance of 1000cd/m<SUP>2</SUP> is obtained, and maintains to 116.3cd/A at 10,000cd/m<SUP>2</SUP>.

Toroidal rotation profile structure in KSTAR L-mode plasmas with mixed heating by NBI and ECH

Shi, Y.J.,Ko, S.H.,Kwon, J.M.,Ko, W.H.,Diamond, P.H.,Yi, S.,Ida, K.,Lee, K.D.,Jeong, J.H.,Seo, S.H.,Hahn, S.H.,Yoon, S.W.,Bae, Y.S.,Terzolo, L.,Yun, G.S.,Bitter, M.,Hill, K. IOP 2016 Nuclear fusion Vol.56 No.1

<P>The structure of the toroidal rotation profile with mixed heating by neutral beam injection (NBI) and electron cyclotron resonance heating (ECH) has been investigated in KSTAR L-mode plasmas. ECH with varying resonance layer positions was used for heating a mix control. The experimental results show that ECH causes a counter-current rotation increment both for off-axis and on-axis ECH heating. For L-mode plasmas, off-axis ECH produces larger counter-current rotation than on-axis ECH. Analysis of ion heat and momentum transport for the ECH L-mode plasmas shows that the electron temperature gradient is the main reason for the degradation of ion heat confinement and also the main driving force for the non-diffusive momentum flux. As a possible mechanism for the counter-current intrinsic torque with ECH, the transition of the turbulence mode from ion temperature gradient (ITG) to the trapped electron mode (TEM) with the resulting sign change of turbulence driven residual stress is suggested. A linear gyro-kinetic analysis shows the ITG  →  TEM transition occurs in a localized region during ECH injection, and the trend of TEM excitation is consistent with the observed macroscopic trend of the toroidal rotation.</P>

Prediction of Digestible and Metabolizable Energy Content of Rice Bran Fed to Growing Pigs

Shi, C.X.,Liu, Z.Y.,Shi, M.,Li, P.,Zeng, Z.K.,Liu, L.,Huang, C.F.,Zhu, Z.P.,Li, D.F. Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.5

Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) content of 19 rice bran samples and to develop prediction equations for DE and ME based on their chemical composition. The 19 rice bran samples came from different rice varieties, processing methods and regions. The basal diet was formulated using corn and soybean meal (74.43% corn and 22.91% soybean meal and 2.66% vitamins and minerals). The 19 experimental diets based on a mixture of corn, soybean meal and 29.2% of each source of rice bran, respectively. In Exp. 1, 108 growing barrows ($32.1{\pm}4.2kg$) were allotted to 1 of 18 treatments according to a completely randomized design with 6 pigs per treatment. The treatment 1 was the control group which was fed with basal diet. The treatments 2 to 18 were fed with experimental diets. In Exp. 2, two additional rice bran samples were measured to verify the prediction equations developed in Exp. 1. A control diet and two rice bran diets were fed to 18 growing barrows ($34.6{\pm}3.5kg$). The control and experimental diets formulations were the same as diets in Exp. 1. The results showed that the DE ranged from 14.48 to 16.85 (mean 15.84) MJ/kg of dry matter while the ME ranged from 12.49 to 15.84 (mean 14.31) MJ/kg of dry matter. The predicted values of DE and ME of the two additional samples in Exp. 2 were very close to the measured values.

MEACHANISM AND METHOD OF DPF REGENERATION BY OXYGEN RADICAL GENERATED BY NTP TECHNOLOGY

Y. X. SHI,Y. X. CAI,X. H. LI,Y. Y. CHEN,D. W. DING,W. TANG 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.6

By using a self-designed non-thermal plasma (NTP) injection system, an experimental study of theregeneration of DPF was conducted at different temperatures, where oxygen as the gas source. The results revealed that PMcan be decomposed to generate CO and CO2 by these active substances O3, O which was generated through the dischargereaction of NTP reactor. With the increasing of test temperature, the mass of C1 (C in CO) shows a overall downward trendwhile the mass of C2 (C in CO2) and C12 (C1 and C2) increase firstly and then decrease. When the test temperature is 80oC, thebackpressure of DPF decreases fastest and the regenerative effect is remarkable. DPF can be regenerated by NTP technologywithout any catalyst at a lower temperature. Compared with the traditional regeneration method, the NTP technology has itssuperiority.

Hybrid Nanocomposites: Processing and Properties

Shi, Y.,Kanny, K.,Jawahar, P. The Korean Society for Composite Materials 2009 Advanced composite materials Vol.18 No.4

Epoxy/S2-glass reinforced composites (SGRPs) infused with Cloisite 30B nanoclays were manufactured using the vacuum assisted resin infusion molding (VARIM) process. Prior to infusion, the matrix and clays were thoroughly mixed using a direct mixing technique (DMT) and a high shear mixing technique (HSMT) to ensure uniform dispersion of the nanoclays. Structures with varying clay contents (1-3 wt%) were manufactured. Both pristine and SGRP nanocomposites were then subjected to mechanical testing. For the specimens manufactured by DMT, the tensile, flexural, and compressive modulus increased with increasing the clay content. Similarly, the tensile, flexural, compressive, interlaminate shear and impact strength increased with the addition of 1 wt% clay: however the trend reversed with further increase in the clay content. Specimens manufactured by HSMT showed superior properties compared to those of nanocomposites containing 1 wt% clay produced by DMT. In order to understand these phenomena a morphological study was conducted. Transmission electron microscopy (TEM) micrographs revealed that HSMT led to better dispersion and changed the nanoclay structure from orderly intercalation to disorderly intercalation giving multi-directional strength.

Structural studies of Mn+ implanted GaN film

Y. Shi,L. Lin,C. Z. Jiang,X. J. Fan 한국진공학회(ASCT) 2003 Applied Science and Convergence Technology Vol.12 No.S1

Wurtzite GaN films are grown by low-pressure MOCVD on (0001)-plane sapphire substrates. The GaN films have a total thickness of 4 ㎛ with a surface Mg-doped p-type layer, which has a thickness of 0.5 ㎛. 90k eV Mn^+ ions are implanted into the GaN films at room temperature with doses ranging from 1×10^(15) to 1×10^(16) ㎝-². After an annealing step at 770℃ in flowing N₂, the structural characteristics of the Mn^+ implanted GaN films are studied by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and atomic force microscopy (AFM). The structural and morphological changes brought about by Mn^+ implantation and annealing are characterized.

Magnetic Characteristics and Structure Studies of Mn-Implanted p-type GaN Films

Y. Shi,C. Z. Jiang,D. J. Fu,L. Lin,강태원,X. J. Fan 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

Wurtzite GaN ¯lms are grown by low-pressure MOCVD on (0001)-plane sapphire substrates. The GaN ¯lms have a total thickness of 4 ¹m with a surface Mg-doped p-type layer which has a thickness of 0.5 ¹m. 90-keV Mn+ ions are implanted into the GaN ¯lms at room temperature with doses ranging from 1 £ 1015 cm¡2 to 5 £ 1016 cm¡2. After an annealing step at about 800 ±C in °owing N2, the magnetism of the Mn-implanted GaN ¯lms is investigated by superconducting-quantum-interference device (SQUID). Despite the diamagnetic background of the undoped sample, the Mn-implanted GaN ¯lms show paramagnetism with dose of 1£1015 cm¡2 and ferromagnetism with a dose of 5 £ 1015 cm¡2 » 5 £ 1016 cm¡2. Combined with the structural characteristics given by X-ray diraction (XRD) and scanning electron microscopy (SEM), the magnetism of the Mn-implanted p-type GaN ¯lms is discussed.

Feasibility of In Vifro Matured Pig Oocytes Following Vitrification

Shi L.Y.,W.Y. Back,Mohana kumar B,G.J. Rho,S.Y. Choe 한국동물생명공학회(구 한국동물번식학회) 2005 Reproductive & Developmental Biology(Supplement) Vol.29 No.2s