scholarly journals COMPUTATIONAL METHOD AND NUMERICAL SIMULATION OF TEMPERATURE FIELD FOR LARGE-SPACE STEEL STRUCTURES IN FIRE

2014 ◽  
pp. 151-178 ◽  
Author(s):  
Sheng-gang Fan ◽  
◽  
Gan-Ping Shu ◽  
Guang-Jun She ◽  
J.Y. Richard Liew ◽  
...  
2017 ◽  
Vol 11 (1) ◽  
pp. 831-838
Author(s):  
Jing Cui ◽  
Lingfeng Yin ◽  
Xiaoming Guo ◽  
Gan Tang

Introduction: The peak temperature is one of the most important factors to evaluate the structural damage. Due to the reduction in the tensile strength of the steel, the structural stress is redistributed and the bearing capacity is decreased at the elevated temperature. Methods: This paper presents an inverse method to evaluate the peak temperature for the steel structures subjected to fire. An initial temperature field is assumed based on the post-fire structural residual displacement, and a temperature iteration function is developed to approach the peak temperature of the structure in fire by minimizing the difference between the measured and numerical results. An experimental study was conducted to investigate the structural behavior of a spatial structure subjected to fire. The temperature and displacement data were recorded. Result and Conclusion: Results show that the measured results have a good agreement with the predicted results, demonstrating that the proposed method in this paper is available for evaluate the peak temperature with a desirable accuracy. The inverse method of the temperature field can provide a theoretical basis for scientifically evaluating the residual displacements of the post-fire structure and formulating reliable repair and reinforcement schemes.


2013 ◽  
Vol 807-809 ◽  
pp. 1505-1513 ◽  
Author(s):  
Amir A.B. Musa ◽  
Xiong Wei Zeng ◽  
Qing Yan Fang ◽  
Huai Chun Zhou

The optimum temperature within the reagent injection zone is between 900 and 1150°C for the NOX reduction by SNCR (selective non-catalytic reduction) in coal-fired utility boiler furnaces. As the load and the fuel property changes, the temperature within the reagent injection zone will bias from the optimum range, which will reduces significantly the de-NOX efficiency, and consequently the applicability of SNCR technology. An idea to improve the NOX reduction efficiency of SNCR by regulating the 3-D temperature field in a furnace is proposed in this paper. In order to study the new method, Computational fluid dynamics (CFD) model of a 200 MW multi-fuel tangentially fired boiler have been developed using Fluent 6.3.26 to investigate the three-fuel combustion system of coal, blast furnace gas (BFG), and coke oven gas (COG) with an eddy-dissipation model for simulating the gas-phase combustion, and to examine the NOX reduction by SNCR using urea-water solution. The current CFD models have been validated by the experimental data obtained from the boiler for case study. The results show that, with the improved coal and air feed method, average residence time of coal particles increases 0.3s, burnout degree of pulverized coal increases 2%, the average temperature at the furnace nose decreases 61K from 1496K to 1435K, the NO emission at the exit (without SNCR) decreases 58 ppm from 528 to 470 ppm, the SNCR NO removal efficiency increases 10% from 36.1 to 46.1%. The numerical simulation results show that this combustion adjustment method based on 3-D temperature field reconstruction measuring system in a 200 MW multi-fuel tangentially fired utility boiler co-firing pulverized coal with BFG and COG is timely and effective to maintain the temperature of reagent injection zone at optimum temperature range and high NOX removal efficiency of SNCR.


Author(s):  
Shaolin Chen ◽  
Hong Zhang ◽  
Liaoping Hu ◽  
Guangqing He ◽  
Fen Lei ◽  
...  

The fatigue life of turbine housing is an important index to measure the reliability of a radial turbocharger. The increase in turbine inlet temperatures in the last few years has resulted in a decrease in the fatigue life of turbine housing. A simulation method and experimental verification are required to predict the life of a turbine housing in the early design and development process precisely. The temperature field distribution of the turbine housing is calculated using the steady-state bidirectional coupled conjugate heat transfer method. Next, the temperature field results are considered as the boundary for calculating the turbine housing temperature and thermomechanical strain, and then, the thermomechanical strain of the turbine housing is determined. Infrared and digital image correlations are used to measure the turbine housing surface temperature and total thermomechanical strain. Compared to the numerical solution, the maximum temperature RMS (Root Mean Square) error of the monitoring point in the monitoring area is only 3.5%; the maximum strain RMS error reached 11%. Experimental results of temperature field test and strain measurement test show that the testing temperature and total strain results are approximately equal to the solution of the numerical simulation. Based on the comparison between the numerical calculation and experimental results, the numerical simulation and test results were found to be in good agreement. The experimental and simulation results of this method can be used as the temperature and strain (stress) boundaries for subsequent thermomechanical fatigue (TMF) simulation analysis of the turbine housing.


2011 ◽  
Vol 71-78 ◽  
pp. 3729-3732
Author(s):  
Ming Zhou ◽  
Zhi Guo Xie ◽  
Xin Tang Wang

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.


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