scholarly journals The Effect of Mixing Rate and Multi Stage Injection on the Internal Flow Field and Combustion Characteristics of DISI Engine Using Methanol-gasoline Blended Fuel at High Speed / High Load Condition

2013 ◽  
Vol 21 (5) ◽  
pp. 15-24
Author(s):  
Jinwoo Bae ◽  
Juhyeong Seo ◽  
Jae Seong Lee ◽  
Ho Young Kim
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Load Condition ◽  
Internal Flow ◽  
High Load ◽  
Combustion Characteristics ◽  
Mixing Rate ◽  
Multi Stage ◽  
High Load Condition ◽  
Blended Fuel

Study on Combustion and Emission Characteristics of Acidic Oil Biodiesel

2014 ◽  
Vol 541-542 ◽  
pp. 982-988
Author(s):  
Jian Wu ◽  
Yang Hua ◽  
Zhan Cheng Wang ◽  
Li Li Zhu ◽  
Hong Ming Wang
Keyword(s):  
Diesel Engine ◽  
Load Condition ◽  
Pressure Rise ◽  
High Load ◽  
Emission Characteristics ◽  
Combustion Heat ◽  
Pressure Maximum ◽  
High Load Condition ◽  
Blended Fuel ◽  
Hc Emissions

In order to develop a new fuel alternative for the diesel engine, experiment of combustion and emission characteristics was carried on a high pressure common rail diesel engine fueled with diesel and acidic oil biodiesel blends, then the results were compared and analyzed. The results indicate that after adding acidic oil biodiesel, the ignition delay is prolonged, combustion pressure, maximum rate of pressure rise and maximum combustion temperature all increase. The maximum combustion heat release rate of blended fuel is higher than diesel at low and middle loads, and lower at high load condition. Compared with diesel, HC emissions of blends decrease dramatically with the increases of blending ratio. NOX emissions of blends are slightly higher than diesel. CO emissions of blends are almost the same as that of diesel. According to the results, acidic oil biodiesel has wide application prospects as an alternative fuel.

scholarly journals Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

scholarly journals Numerical simulation of the non-uniform flow in a full-annulus multi-stage axial compressor with the harmonic balance method

2020 ◽  
Vol 12 (3) ◽  
pp. 168781401989721 ◽  
Author(s):  
Haiou Sun ◽  
Meng Wang ◽  
Zhongyi Wang ◽  
Song Wang ◽  
Franco Magagnato
Keyword(s):  
Flow Field ◽  
Harmonic Balance ◽  
Axial Compressor ◽  
Harmonic Balance Method ◽  
Internal Flow ◽  
Uniform Flow ◽  
Experimental Results ◽  
Balance Method ◽  
Operating Characteristics ◽  
Multi Stage

To improve the understanding of unsteady flow in modern advanced axial compressor, unsteady simulations on full-annulus multi-stage axial compressor are carried out with the harmonic balance method. Since the internal flow in turbomachinery is naturally periodic, the harmonic balance method can be used to reduce the computational cost. In order to verify the accuracy of the harmonic balance method, the numerical results are first compared with the experimental results. The results show that the internal flow field and the operating characteristics of the multi-stage axial compressor obtained by the harmonic balance method coincide with the experimental results with the relative error in the range of 3%. Through the analysis of the internal flow field of the axial compressor, it can be found that the airflow in the clearance of adjacent blade rows gradually changes from axisymmetric to non-axisymmetric and then returns to almost completely axisymmetric distribution before the downstream blade inlet, with only a slight non-axisymmetric distribution, which can be ignored. Moreover, the slight non-axisymmetric distribution will continue to accumulate with the development of the flow and, finally, form a distinct circumferential non-uniform flow field in latter stages, which may be the reason why the traditional single-passage numerical method will cause certain errors in multi-stage axial compressor simulations.

Study on the Turbulent Injury Principle of Blood in the High-Speed Spiral Blood Pump

2011 ◽  
Vol 393-395 ◽  
pp. 992-995
Author(s):  
Zhong Yun ◽  
Chuang Xiang ◽  
Xiao Yan Tang ◽  
Fen Shi
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Blood Cell ◽  
Turbulent Flow ◽  
Red Blood Cell ◽  
Blood Cells ◽  
High Speed ◽  
Internal Flow ◽  
Blood Pump ◽  
Turbulent Flow Field

The strongly swirling turbulent flow in the internal flow field of a high-speed spiral blood pump(HSBP), is one of important factors leading to the fragmentation of the red blood cell(RBC) and the hemolysis. The study on the turbulent injure principle of blood in the HSBP is carried out by using the theory of waterpower rotated flow field and the hemorheology. The numerical equation of the strongly swirling turbulent flow field is proposed. The largest stable diameter of red blood cells in the turbulent flow field is analyzed. The determinant gist on the red blood cell turbulent fragmentation is obtained. The results indicate that in the HSMP, when turbulent flow is more powerful, shear stress is weaker, the vortex mass with energy in flow field may cause serious turbulent fragmentation because of the diameter which is smaller than the RBC’s. The RBC’s turbulent breakage will occur when the Weber value is larger than 12.

Effect of Load-Relieving Structure against Overload under High Overload

2013 ◽  
Vol 328 ◽  
pp. 421-425
Author(s):  
Quan Li Ning ◽  
Jun Li ◽  
Dong Chen ◽  
Gao Peng Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Constitutive Equation ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Load Condition ◽  
High Load ◽  
Dynamical Response ◽  
Response Distribution ◽  
High Load Condition

Three-dimensional visco-elastic lame deformation incremental constitutive equation is derived based on Total Lagrangian method, and structural dynamical response distribution in the grain during launching is simulated numerically by finite element method under high load condition for projectile-based equipment, the equivalent stress in the bottom of load-relieving structure and the Y-displacement in the top of load-relieving structure are calculated. The results show that the stress is ameliorated after the function of load-relieving subassembly, and it can decrease impact. Also Y-displacement is accord with limit request, and when reaching the maximum, the transmutation will be comeback.

Experimental Study of EGR on Performance and Emissions of a Turbocharged DME Engine

2014 ◽  
Vol 886 ◽  
pp. 257-261
Author(s):  
Jun Hua Wu ◽  
Fu Shan Zuo ◽  
Yong Hui Zhang
Keyword(s):  
Experimental Study ◽  
Fuel Consumption ◽  
Substantial Reduction ◽  
Load Condition ◽  
High Load ◽  
Reduction Of No ◽  
Low Load ◽  
Emission Behavior ◽  
High Load Condition

This paper presents anexperimental study on reduction of NOx emission of a turbochargedengine fuelled with DME by means of EGR. Effects of EGR rate on engineefficiency and emission behavior was evaluated. The results show that the EGRcould be used as an effective way to reduce NOx emission. NOx isreduced almost linearly with increase of EGR rate. At low load condition, theNOx emission is reduced by 80% with 40% EGR rate without any economypenalty. At high load condition, the same substantial reduction of NOx couldbe achieved with only 20% EGR rate. While the HC and CO emissions are increasedwith increase of EGR rate. However, it is worth noting that EGR had a negativeeffect on fuel consumption at high load. Low EGR ratio should be taken at highengine load condition.

Detailed Flow Investigations Within a High-Speed Centrifugal Compressor Impeller

1976 ◽  
Vol 98 (3) ◽  
pp. 390-399 ◽  
Author(s):  
D. Eckardt
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
High Speed ◽  
Internal Flow ◽  
Suction Side ◽  
Turbulence Structure ◽  
Wake Interaction ◽  
Compressor Impeller ◽  
Channel Curvature ◽  
Relative Flow

Detailed accurate measurements of velocities, directions, and fluctuation intensities were performed with a newly developed laser velocimeter in the internal flow field of a radial discharge impeller, running at tip speeds up to 400 m/s. Relative flow distributions are presented in five measurement areas from inducer inlet to impeller discharge. The impeller flow pattern, which coincides largely with potential-theory calculations in the axial inducer, becomes more and more reversed when the flow separates from the blade suction side, developing a rapidly increasing wake in the radial impeller. The observed secondary flow pattern and effects of channel curvature and system rotation on turbulence structure are discussed with respect to separation onset and jet/wake interaction.

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