Numerical Analysis on Combustion Flow Characteristics of Jet-Stabilized Combustor with Different Geometry

2021 ◽  
Author(s):  
Le Tian ◽  
Haijun Sun ◽  
Yihua Xu ◽  
Ping Jiang ◽  
Hongyi Lu ◽  
...  
2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Tetsuaki Takeda

When a depressurization accident of a very-high-temperature reactor (VHTR) occurs, air is expected to enter into the reactor pressure vessel from the breach and oxidize in-core graphite structures. Therefore, in order to predict or analyze the air ingress phenomena during a depressurization accident, it is important to develop a method for the prevention of air ingress during an accident. In particular, it is also important to examine the influence of localized natural convection and molecular diffusion on the mixing process from a safety viewpoint. Experiment and numerical analysis using a three-dimensional (3D) computational fluid dynamics code have been carried out to obtain the mixing process of two-component gases and the flow characteristics of localized natural convection. The numerical model consists of a storage tank and a reverse U-shaped vertical rectangular passage. One sidewall of the high-temperature side vertical passage is heated, and the other sidewall is cooled. The low-temperature vertical passage is cooled by ambient air. The storage tank is filled with heavy gas and the reverse U-shaped vertical passage is filled with a light gas. The result obtained from the 3D numerical analysis was in agreement with the experimental result quantitatively. The two component gases were mixed via molecular diffusion and natural convection. After some time elapsed, natural circulation occurred through the reverse U-shaped vertical passage. These flow characteristics are the same as those of phenomena generated in the passage between a permanent reflector and a pressure vessel wall of the VHTR.


2003 ◽  
Author(s):  
Duk-Sang Kim ◽  
Yeun-Jun Yoo ◽  
Yong-Seok Cho ◽  
In-Yong Ohm

2019 ◽  
Vol 356 ◽  
pp. 858-870 ◽  
Author(s):  
Hanru Liu ◽  
Fuguo Jia ◽  
Yawen Xiao ◽  
Yanlong Han ◽  
Gengrun Li ◽  
...  

Author(s):  
Jang Il Lee ◽  
Ae Ju Cheong ◽  
Bok Ki Min

In this numerical study, Commercial CFD (Computational Fluid Dynamics) code, ANSYS CFX ver. 17.1, is used to analyze the 3-Dimensional flow characteristics through orifice plate (β = 0.6) with two 90 degree bends in different planes. The purpose of this numerical study is to evaluate measurement accuracy and flow characteristics of orifice flowmeter depending on upstream straight length from 12D to 56D. Thus, numerical calculations of pressure drop caused by swirling flow and distortion of axial velocity profile on orifice plate are performed by using numerical analysis. In addition, numerical analysis results are compared with recommended upstream straight length of ASME Performance Test Codes 19.5 for orifice plates and nozzles. The results show that if upstream straight length of orifice flowmeter is more than 40D, there is a little deviation of differential pressure. Moreover, it is found that up-down asymmetry of recirculation zones is relatively attenuated as the upstream straight length increases.


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