scholarly journals Study on the influence of radius of curvature on flow resistance in spiral pipe

2021 ◽  
Vol 237 ◽  
pp. 03013
Author(s):  
Wenqiang Li ◽  
Hui Qi ◽  
Yongfeng Yang ◽  
Guojun Zhao ◽  
Rong Liu ◽  
...  
Keyword(s):  
Numerical Calculation ◽  
Wind Speed ◽  
Flow Resistance ◽  
Fluid Flows ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Change Rate ◽  
Linear Pattern ◽  
Offset Distance ◽  
Numerical Calculation Method

With the continuous development of west of China, a new kind of tunnel, namely spiral tunnel, has appeared in the expressway. Due to the special linear pattern, the resistance of airflow in spiral tunnel has been found to change, but there are few relevant researches at present. Therefore, numerical calculation method is used to study the variation of flow resistance in spiral pipe with different curvature. The results show that when the fluid flows in the spiral pipe, the wind speed is not uniformly distributed. The highest speed is not in the center of the pipe, but on the outside of the pipe, and the offset distance decreases with the increase of the radius of curvature. In addition, the change of flow resistance in spiral pipe is studied, and it is found that the change rate of flow resistance decreases with the increase of curvature radius. It shows that the radius of curvature is negatively correlated with the flow resistance.

Determination Method of Elasto-Plastic Correction Factor of TA16 Titanium Alloy Based On RCC-M Code Methodology

2021 ◽  
Author(s):  
Xuejiao Shao ◽  
Juan Du ◽  
Liping Zhang ◽  
Hai Xie ◽  
Jun Tian ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Numerical Calculation ◽  
Austenitic Stainless Steel ◽  
Constitutive Model ◽  
Correlation Coefficient ◽  
Correction Factor ◽  
Calculation Method ◽  
Plastic Correction ◽  
Numerical Calculation Method

Abstract In the code for nuclear equipment, the elasto-plastic correction factor KE is a correction factor when the stress range exceeds the yield limit for simplified elasto-plastic fatigue analysis. The parameters and expressions of KE for commonly used materials (such as austenitic stainless steel) are given in the RCC-M and ASME code, but the parameters of KE for titanium alloy materials is lacking. Based on the cyclic elasto-plastic constitutive model of Z2CND18.12 (nitrogen control) and KE parameters of austenitic stainless steel given in the code, considering various sensitive factors, a numerical calculation method for determining KE correlation coefficient is established. The elasto-plastic constitutive model of TA16 alloy with nonlinear kinematic hardening was established by the uniaxial tension, strain and stress cycling tests of TA16 titanium alloy. Based on the numerical calculation method of KE and the constitutive model of TA16 titanium alloy, the expression and correlation coefficient of KE for TA16 titanium alloy were determined.

Precise grading of surrounding rock based on the numerical calculation of the jointed rock mass

2022 ◽  
pp. 1-32
Author(s):  
Dan Huang ◽  
Xiao-Qing Li ◽  
Wen-Chao Song
Keyword(s):  
Rock Mass ◽  
Numerical Calculation ◽  
Calculation Method ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Geological Survey ◽  
Survey Method ◽  
Synthetic Rock ◽  
Numerical Calculation Method

In this study, grading of surrounding rock was based on rock mass basic quality (BQ) values according to the specifications in China. Numerical approach was to construct synthetic rock mass (SRM) model to represent the jointed rock mass, and obtain the strength of the rock mass. It represented intact rock by the bonded particle model (BPM), and represent joint behaviour by the smooth joint model (SJM) to construct the discrete fracture network (DFN). In the Hongtuzhang Tunnel, the micro properties of granite cores with different weathered degrees were determined by the validation process, and the calculation representative elementary volume (REV) of surrounding rock was 15 m×15 m. Five slightly weathered, three slightly to moderately weathered, and two moderately weathered granite surrounding rock mass models were established based on the probability distribution of joint sets in each borehole, the conversion BQ value was acquired according by the calculated strength of rock mass model. It was discussed the differences of surrounding rock grades between the geological survey method and the numerical calculation method, and then found that the geological survey report is higher than the numerical calculation method predicted. And the numerical calculation is consistent with the actual excavation of rock mass at borehole A1388.

scholarly journals Simple numerical calculation method of flow velocity on roof of train running in tunnel

2018 ◽  
Vol 5 (3) ◽  
pp. 17-00545-17-00545 ◽  
Author(s):  
Katsuhiro KIKUCHI ◽  
Yuhei NOGUCHI ◽  
Koji NAKADE ◽  
Shinya MASHIMO
Keyword(s):  
Numerical Calculation ◽  
Flow Velocity ◽  
Calculation Method ◽  
Numerical Calculation Method

Numerical calculation method of inter-strand coupling current losses in superconducting conductors

Cryogenics ◽  
1989 ◽  
Vol 29 (7) ◽  
pp. 741-747 ◽  
Author(s):  
F. Sumiyoshi ◽  
H. Kasahara ◽  
T. Kawashima ◽  
T. Tanaka
Keyword(s):  
Numerical Calculation ◽  
Calculation Method ◽  
Numerical Calculation Method ◽  
Coupling Current

Analysis of Flow Resistance Inside Microchannels With Different Inlet Configurations Using Micro-PIV System

2003 ◽  
Author(s):  
Sang-Joon Lee ◽  
Guk-Bae Kim
Keyword(s):  
Flow Resistance ◽  
Reduction Rate ◽  
Flow Characteristics ◽  
Entrance Region ◽  
Curvature Radius ◽  
Microfluidic Chips ◽  
Mean Velocity ◽  
Dimethyl Siloxane ◽  
Micro Piv ◽  
Macro Scale

Most microfluidic chips consist of several microchannels inside. In order to design microfluidic chips efficiently, it is important to predict the flow passage and to understand the flow characteristics on the chip. In this study, the flow structure inside microchannels has been investigated using a micro-PIV system. We focused on the flow resistance with respect to the inlet configuration of microchannels. The microchannels made of poly-dimethyl-siloxane (PDMS) material were fabricated by a micro-molding technique using SU-8 (photoresist) master. The width (w) and depth of the microchannels were fixed as 100 μm and 58 μm, respectively. Six different inlet configurations with curvature radii in the ranges from r = 0.2w to 1.5w were tested in this study. As a result, with increasing the curvature radius of the inlet corner, the streamwise mean velocity develops slowly in the entrance region, but the fully developed velocity at further downstream is increased. When the curvature radius is larger than r = 0.6w, the reduction rate of flow resistance is not so significant. For the microchannels with r = 0.6w, 0.8w and 1.0w the downstream mean velocity at channel center has nearly the same value of about 276 mm/sec, 10.5% larger than that of r = 0.2w. The simple rounding of microchannel inlet corner reduces flow resistance effectively by smoothing the incoming flow. The length of entrance region is much smaller than that of macro-scale channel.

IDENTIFICATION OF CURVATURE RADIUS FOR CURVED SECTIONS ON FOREST ROADS IN THE PROCESS OF UTILISATION

2021 ◽  
Vol 14(63) (1) ◽  
pp. 47-56
Author(s):  
Ihor RUDKO ◽  
Borys BAKAY ◽  
Abdullah AKAY ◽  
Vasyl BARYLIAK ◽  
Stanislav HORZOV
Keyword(s):  
Technical Information ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Forest Roads ◽  
Forest Road ◽  
Advantages And Disadvantages ◽  
Natural Production ◽  
Angle Deviation ◽  
Road Projects ◽  
Selection Of

This article reviews the problem of measuring the actual radius of curvature for curved sections of existing forest roads, as forestry enterprises require reliable technical information about the current conditions of operated transport networks. It was identified that at this moment, a selection of methods are used for measuring the radii of horizontal curved sections of roads, which have certain advantages and disadvantages in specific natural production conditions. For calculating the radius of curvature for auto forest road projects it is recommended to apply the method of measured angles by chord angle deviation, which is sufficiently accurate for engineering purposes and does not require usage of special high-precision equipment and tools.

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