Heat Transfer at Particle‐Tube Wall Contact Point: Impact of Catalyst Configuration on Hotspot

2021 ◽  
Author(s):  
Mahdi Zare ◽  
Seyed Hassan Hashemabadi ◽  
Mohammad Sheikhi
Keyword(s):  
Heat Transfer ◽  
Tube Wall ◽  
Contact Point

scholarly journals Numerical Analysis on Rib-Tubes of Seawater Open Rack Vaporizer With the Spoiler Lever

2017 ◽  
Vol 24 (s2) ◽  
pp. 14-21
Author(s):  
Su Houde ◽  
Yu Shurong ◽  
Fan Jianling ◽  
Wei Xing
Keyword(s):  
Heat Transfer ◽  
Tube Wall ◽  
Small Difference ◽  
Operating Temperature ◽  
Operating Parameter ◽  
Tube Model ◽  
Heat Transfer Tube ◽  
Transfer Tube ◽  
Gasification Efficiency ◽  
Gas Ratio

Abstract In order to explore a more reasonable structure and operating parameter, guide the design and improve the gasification of seawater Open Rack Vaporizer (ORV), Research on the rules of seawater that flows and heat transfer in the ORV tube was studied in this paper. By simplifying the model, heat transfer tube model with spoiler lever was obtained and simulated, the distribution of temperature field, gas ratio, velocity field and press field in rib tube were analyzed, and different inlet velocity of LNG, roughness of the tube wall both effected on the overall gasification, the results shows that the actual gasification efficiency from heat transfer tube is higher than normal, small difference of gas ratio outlet, velocity and temperature are both lower, LNG could be easer gasified at operating temperature between -162°C~+3°C than that between -162°C~+0°C.

Convective Heat Transfer Enhancement in a Circular Tube Using Twisted Tape

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Zhi-Min Lin ◽  
Liang-Bi Wang
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Convective Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Secondary Flow ◽  
Convective Heat ◽  
Tube Wall ◽  
Twisted Tape ◽  
Transfer Enhancement ◽  
Thermal Boundary Conditions

The secondary flow has been used frequently to enhance the convective heat transfer, and at the same flow condition, the intensity of convective heat transfer closely depends on the thermal boundary conditions. Thus far, there is less reported information about the sensitivity of heat transfer enhancement to thermal boundary conditions by using secondary flow. To account for this sensitivity, the laminar convective heat transfer in a circular tube fitted with twisted tape was investigated numerically. The effects of conduction in the tape on the Nusselt number, the relationship between the absolute vorticity flux and the Nusselt number, the sensitivity of heat transfer enhancement to the thermal boundary conditions by using secondary flow, and the effects of secondary flow on the flow boundary layer were discussed. The results reveal that (1) for fully developed laminar heat convective transfer, different tube wall thermal boundaries lead to different effects of conduction in the tape on heat transfer characteristics; (2) the Nusselt number is closely dependent on the absolute vorticity flux; (3) the efficiency of heat transfer enhancement is dependent on both the tube wall thermal boundaries and the intensity of secondary flow, and the ratio of Nusselt number with twisted tape to its counterpart with straight tape decreases with increasing twist ratio while it increases with increasing Reynolds number for both uniform wall temperature (UWT) and uniform heat flux (UHF) conditions; (4) the difference in the ratio between UWT and UHF conditions is also strongly dependent on the conduction in the tape and the intensity of the secondary flow; and (5) the twist ratio ranging from 4.0 to 6.0 does not necessarily change the main flow velocity boundary layer near tube wall, while Reynolds number has effects on the shape of the main flow velocity boundary layer near tube wall only in small regions.

Influences of tube wall on the heat transfer and flow instability of various supercritical pressure fluids in a vertical tube

2019 ◽  
Vol 147 ◽  
pp. 242-250 ◽  
Author(s):  
Zhen Zhang ◽  
Chenru Zhao ◽  
Xingtuan Yang ◽  
Peixue Jiang ◽  
Shengyao Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Instability ◽  
Tube Wall ◽  
Vertical Tube ◽  
Supercritical Pressure

scholarly journals Steady Laminar Heat Transfer in a Circular Tube with Conduction in Tube Wall

1974 ◽  
Vol 38 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Shigeru Mori ◽  
Mikio Sakakibara ◽  
Akira Tanimoto
Keyword(s):  
Heat Transfer ◽  
Circular Tube ◽  
Tube Wall ◽  
Steady Laminar

3D Numerical Simulation of Fluid Flow and Heat Transfer for Asymmetric Spiral-Gear Inserts in a Tube

2011 ◽  
Vol 130-134 ◽  
pp. 1686-1690 ◽  
Author(s):  
De Qi Peng ◽  
Wei Qiang Wang ◽  
Tian Lan Yu ◽  
Biao Wei ◽  
Yu Zhou ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Tube Wall ◽  
Convection Heat Transfer ◽  
Engineering Application ◽  
Tangential Velocity ◽  
Smooth Tube ◽  
Tube Heat Exchanger ◽  
Flow And Heat Transfer

For solving cleaning fouling online for shell-and-tube heat exchanger，an asymmetric spiral-gear cleaning technology is presented. The RNGk-εturbulent model is used to simulate the fluid flow and heat transfer of the tube with the spiral-gear. Its velocity and turbulent intensity field, convection heat transfer characteristic and resistance property are analyzed. Numerical simulation results shows that radial velocity is larger in the annular area near the tube wall than that in the smooth tube. Tangential velocity in the diameter area corresponding to the width of spiral-gear insertion increases with radius，but it decreases with radius in the annular clearance between the insert and the tube wall. However, fluid tangential motion of the smooth tube is only stochastic，and its tangential velocity is lower several orders of magnitude than that for the tube with the insertions. The average surface heat transfer coefficient of the spiral-gear-inserted tube wall is increased nearly 88% than that from the smooth tube wall. In addition, the pressure drop caused by spiral-gear inserts is in the permissible range of engineering application. The inserts is applicable to the heat exchangers at a flow rate lower than 0.8 m·s-1.

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