scholarly journals Effects of Exhaust Pipe and Diffuser Shapes on Purification Efficiency of Exhaust Gas Three-way Catalyzer for Gasoline Engines - Investigation by Three-dimensional Numerical Simulation of Thermo-fluid Flow and Catalytic Reaction

2009 ◽  
Vol 44 (3) ◽  
pp. 477-483
Author(s):  
Hideki Takase ◽  
Toshimasa Kotani ◽  
Yogo Takada ◽  
Tomoyuki Wakisaka
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Catalytic Reaction ◽  
Three Dimensional ◽  
Exhaust Pipe ◽  
Exhaust Gas ◽  
Gasoline Engines ◽  
Purification Efficiency

315 Three-Dimensional Numerical Simulation of the Thermo-Fluid and Catalytic Reaction in an Exhaust Gas Three-Way Catalyzer

2005 ◽  
Vol 2005.80 (0) ◽  
pp. _3-29_-_3-30_
Author(s):  
Toshimasa KOTANI ◽  
Kazuma ITO ◽  
Sang-kyu KIM ◽  
Yogo TAKADA ◽  
Tomoyuki WAKISAKA
Keyword(s):  
Numerical Simulation ◽  
Catalytic Reaction ◽  
Three Dimensional ◽  
Exhaust Gas

scholarly journals Study on Valve Strategy and Fuel Benefits of Skip Fire Based on Electromagnetic Valve Train

2018 ◽  
Vol 202 ◽  
pp. 02003
Author(s):  
Maoyang Hu ◽  
Siqin Chang
Keyword(s):  
Control Method ◽  
Valve Train ◽  
Normal Operation ◽  
Energy Losses ◽  
Exhaust Pipe ◽  
Firing Cycle ◽  
Exhaust Gas ◽  
Gasoline Engines ◽  
Electromagnetic Valve ◽  
Brake Mean Effective Pressure

Cylinder deactivation (CDA) is a fuel consumption reduction technology for gasoline engines. Skip fire is a new type of CDA because the load and the density of firing cylinder are in proportion to the torque demand. However, it is difficult to realize because valves need to be switched between valve deactivation and normal operation stroke by stroke. The Electromagnetic valve train (EMVT) provides a fully flexible control method to achieve skip fire. In the paper, a new skip fire strategy based on electromagnetic intake valve train (EMIV) is proposed. Then, the oxygen concentration of the exhaust pipe, energy losses, in-cylinder pressure of the skipped cycle and exhaust gas recirculation (EGR) rate of the firing cycle are studied by the 1D simulation in GT-Power. The results shows the majority of gas sucked into the skipped cylinder is exhaust gas by reasonable control of IVO and IVC, and the exhaust oxygen-rich can be avoided. Meanwhile, EGR rate of the firing cylinder and energy losses of the skipped cylinder are maintained at lower level. At the conditions of 1200 and 1600 rpm, fuel economy has been improved respectively 8.1%-16.6% and 6.4%-14.6% when the brake mean effective pressure (BMEP) ranges from 0.4MPa to 0.2MPa.

Numerical simulation of three-dimensional passive micromixer based on the principle of Koch fractal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Siyue Xiong ◽  
Xueye Chen
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Cross Section ◽  
Three Dimensional ◽  
Mixing Efficiency ◽  
Mixing Performance ◽  
Chaotic Convection ◽  
Passive Micromixer ◽  
Koch Fractal ◽  
Koch Fractal Principle

Abstract In this paper, We arrange the obstacles based on the Koch fractal principle (OKF) in the micromixer. By changing the fluid flow and folding the fluid, a better mixing performance is achieved. We improve the mixing efficiency by placing OKF and changing the position of OKF, then we studied the influence of the number of OKF and the height of the micromixer on the mixing performance. The results show that when eight OKF are staggered in the microchannel and the height is 0.2 mm, the mixing efficiency of the OKF micromixer can reach 97.1%. Finally, we compared the velocity cross section and velocity streamline of the fluid, and analyzed the influence of OKF on the concentration trend. Through analysis, it is concluded that OKF can generate chaotic convection in the fluid, and enhance the mixing of fluids by generating vortices and folding the fluid. It can effectively improve the mixing efficiency of the micromixer.

scholarly journals Numerical Simulation of Full-Scale Three-Dimensional Fluid Flow in an Oscillating Reactor

2021 ◽  
Vol 9 ◽  
Author(s):  
Houjun Gong ◽  
Mengqi Wu
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Flow Field ◽  
Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Full Scale ◽  
Variation Patterns ◽  
Oscillating Motion ◽  
Resistance Coefficients

Marine reactors are subjected to additional motions due to ocean conditions. These additional motions will cause large fluctuation of flow rate and change the coolant flow field, making the system unstable. Therefore, in order to understand the effect of oscillating motion on the flow characteristics, a numerical simulation of fluid flow is carried out based on a full-scale three-dimensional oscillating marine reactor. In this study, the resistance coefficients of the lattice, rod buddle and steam generator are fitted, and the distribution of flow rate, velocity as well as pressure in different regions is investigated through the standard model. After additional oscillation is introduced, the flow field in an oscillating reactor is presented and the effect of oscillating angle and elevation on the flow rate is investigated. Results show that the oscillating motion can greatly change the flow field in the reactor; most of the coolant circulates in the downcommer and lower head with only a small amount of coolant entering the core; the flow fluctuation period is consistent with the oscillating period, and the flow variation patterns under different oscillating conditions are basically the same; since the flow amplitude is related to oscillating speed, the amplitude of flow rate rises when decreasing the maximum oscillating angle; the oscillating elevation has little effect on the flow rate.

Numerical Simulation of Multiple Seeds Interaction During Three-Dimensional Dendritic Solidification With Fluid Flow

2009 ◽  
Author(s):  
Ikroh Yoon ◽  
Seungwon Shin
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Solidification Process ◽  
Small Scale ◽  
Reconstruction Method ◽  
External Fluid ◽  
Fluid Convection ◽  
Dimensional Simulation

Most material of engineering interest undergoes solidification process from liquid to solid state which governs the microstructure of materials. Identifying the growth characteristic of the microstructure during the solidification process is essential to determine the physical properties of final product. Numerical simulation can provide valuable information during solidification process since heat and mass transfer associated with micro-structural growth of dendrite is in greatly small scale which is almost impossible to obtain by experiments. In real situations, dendrite tends to grow from multiple seeds as well as with external fluid flow. Growth characteristics of the dendrites will be greatly influenced by both external fluid convection and interaction between dendrites. In this paper, three-dimensional numerical simulation of multiple dendritic growth during solidification process with melt fluid convection is presented. The high-order Level Contour Reconstruction Method (LCRM), a hybrid form of Front-Tracking and Level-Set, is used to track the moving liquid-solid interface explicitly and sharp interface technique has been used to implement correct phase changing boundary conditions on the moving interface. To get the indicator function and the interface curvature more efficiently and accurately for three-dimensional simulation, we have generated the distance function directly from the interface. The method is validated by comparing with other numerical technique and showed good agreements. Three-dimensional results showed clear difference compared to two-dimensional simulation on growth behavior, especially with multiple seeds.

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