scholarly journals Inhibition of temperature runaway phenomenon in the Sabatier process using bed dilution structure: LBM-DEM simulation

2021 ◽  
Author(s):  
Yixiong LIN ◽  
Chen Yang ◽  
Cheolyong Choi ◽  
Wei Zhang ◽  
Kazui Fukumoto ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Conversion Rate ◽  
Catalyst Deactivation ◽  
Kinetic Scheme ◽  
Industrial Applications ◽  
Dilution Method ◽  
Carbon Conversion ◽  
Packing Structure ◽  
Carbon Dioxide Utilization ◽  
Boltzmann Method

The Sabatier process is promising for carbon dioxide utilization and energy storage. However, the serious problem that limits more comprehensive industrial applications is catalyst deactivation due to the temperature runaway phenomenon. The inert particle dilution approach, including the mixing dilution method and layered dilution method is applied to solve this problem. Based on the lattice kinetic scheme-lattice Boltzmann method (LKS-LBM), the effects of three parameters in bed dilution structure reconstructed by the discrete element method (DEM) on temperature distribution and carbon conversion rate were discussed, so as to investigate the relationship between packing structure and temperature distribution. Furthermore, numerical results indicated that an optimal bed dilution structure, which not only can control the peak temperature below the critical temperature to avoid coking and sintering of catalyst, but also can improve the carbon conversion rate by almost 18% compared with the structure without dilution under the same circumstance.

An Innovative Thermal Analysis Model for Continuous Operation of a Solar Collector

2020 ◽  
Author(s):  
Arman Nokhosteen ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Solar Irradiation ◽  
Average Error ◽  
Solar Collectors ◽  
Analysis Model ◽  
Night Time ◽  
Working Cycle ◽  
Time Operation ◽  
Boltzmann Method

Abstract Heat pipe evacuated tube solar collectors (HPETCs) are a type of solar collectors widely used in solar water heating (SWH) technologies. In order to optimize the design of SWHs, understanding the heat transfer phenomena in HPETCs is of paramount importance. The complexity of the heat transfer processes involved in modelling a collector’s performance render direct numerical simulations (DNS) computationally cumbersome. In this work, a novel hybrid numerical method is employed in order to simulate the thermal behaviour of HPETCs, both during day and night time operation. This method is comprised of a previously developed resistance network based proper orthogonal decomposition (RNPOD) method for simulation during operation hours were solar irradiation values are greater than zero; after which, an in-house code based on Lattice Boltzmann method (LBM) has been utilized for simulation when irradiance is zero. This hybrid method is able to reduce simulation time and take into account the ambient working conditions of the collector and therefore, provide an accurate assessment of the temperature distribution inside the collector during the entirety of its operation during a full working cycle. The obtained results of this study are cross-validated with the previous experimental work of the authors, illustrating that the model is able to predict the peripheral temperature distribution with an average error of less than 10%.

scholarly journals A New Algorithm for Reconstructing Two-Dimensional Temperature Distribution by Ultrasonic Thermometry

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xuehua Shen ◽  
Qingyu Xiong ◽  
Weiren Shi ◽  
Shan Liang ◽  
Xin Shi ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Ultrasound Velocity ◽  
Least Square Method ◽  
Reconstruction Algorithm ◽  
Industrial Applications ◽  
Least Square ◽  
Distribution Models ◽  
Practical Applications ◽  
Reconstruction Performance ◽  
Reconstructed Temperature

Temperature, especially temperature distribution, is one of the most fundamental and vital parameters for theoretical study and control of various industrial applications. In this paper, ultrasonic thermometry to reconstruct temperature distribution is investigated, referring to the dependence of ultrasound velocity on temperature. In practical applications of this ultrasonic technique, reconstruction algorithm based on least square method is commonly used. However, it has a limitation that the amount of divided blocks of measure area cannot exceed the amount of effective travel paths, which eventually leads to its inability to offer sufficient temperature information. To make up for this defect, an improved reconstruction algorithm based on least square method and multiquadric interpolation is presented. And then, its reconstruction performance is validated via numerical studies using four temperature distribution models with different complexity and is compared with that of algorithm based on least square method. Comparison and analysis indicate that the algorithm presented in this paper has more excellent reconstruction performance, as the reconstructed temperature distributions will not lose information near the edge of area while with small errors, and its mean reconstruction time is short enough that can meet the real-time demand.

EFFECT OF HEATED REGION ON TEMPERATURE DISTRIBUTION WITHIN TISSUE DURING MAGNETIC FLUID HYPERTHERMIA USING LATTICE BOLTZMANN METHOD

2011 ◽  
Vol 11 (02) ◽  
pp. 457-469 ◽  
Author(s):  
ALI AKBAR GOLNESHAN ◽  
MANSOUR LAHONIAN
Keyword(s):  
Temperature Distribution ◽  
Magnetic Fluid ◽  
Lattice Boltzmann ◽  
Volume Fraction ◽  
Transfer Problem ◽  
Biological Tissues ◽  
Lattice Boltzmann Model ◽  
Heated Region ◽  
Magnetic Fluid Hyperthermia ◽  
Boltzmann Method

This work uses the lattice Boltzmann model (LBM) to solve the Pennes bio-heat equation (BHE) to predict the temperature rise behavior occurring in cylindrical biological tissues during magnetic fluid hyperthermia (MFH). Therefore, LBM is extended to solve the bio-heat transfer problem with curved boundary conditions. Effect of magnetic nanoparticles' (MNPs) volume fraction as well as the vastness of heated region on the temperature distribution are shown. The analytical and numerical finite difference solutions reveal the accuracy of the model.

A New Approach to Solve Inverse Boundary Design of a Radiative Enclosure with Specular-Diffuse Surfaces

2021 ◽  
Author(s):  
Babak Mosavati ◽  
Maziar Mosavati
Keyword(s):  
Heat Flux ◽  
Monte Carlo ◽  
Temperature Distribution ◽  
Monte Carlo Method ◽  
Industrial Applications ◽  
Heat Fluxes ◽  
Uniform Heat Flux ◽  
Uniform Temperature ◽  
Inverse Boundary ◽  
Uniform Temperature Distribution

Abstract The maintenance of uniform temperature distribution affects the efficiency in the most industrial applications. In the current study, a novel strategy has been developed for inverse radiative boundary design problems in radiant enclosures. This study presents the Backward Monte Carlo method to investigate the inverse boundary design of an enclosure composed of specular and diffuse surfaces. A new optimized Monte Carlo method is proposed to determine the temperature distribution of heaters to achieve desirable prescribed uniform heat flux on the design surfaces. The proposed approach is highly efficient and simple to implement with appropriate results. The evaluated heat fluxes on design surfaces and temperature distribution of heaters are compared with the case where the reradiating walls are assumed to be perfectly diffuse. In the proposed approach, for a specific range of specularity, the absorptivity of the reradiating surfaces does not affect the temperature distribution of heaters. Compared to the diffuse walls, the specular walls have more uniform temperature distribution and heat flux of heaters. This finding will provide insight into solar furnaces design to enhance temperature uniformity, making specular surfaces suitable in many industrial applications.

scholarly journals Evaluation of heating uniformity in radio frequency heating systems using carrot and radish

2016 ◽  
Vol 30 (4) ◽  
pp. 465-473 ◽  
Author(s):  
Ling Kong ◽  
Min Zhang ◽  
Yuchuan Wang ◽  
Benu Adhikari ◽  
Zaixing Yang
Keyword(s):  
Temperature Distribution ◽  
Radio Frequency ◽  
Temperature Rise ◽  
Industrial Applications ◽  
Food Samples ◽  
Central Position ◽  
Rf Heating ◽  
Radio Frequency Heating ◽  
Heating Uniformity ◽  
Frequency Heating

Abstract Lack of heating uniformity is a major problem impeding the broader adaptation of radio frequency heaters in industrial applications. The overall aim of this study was to evaluate the uniformity of heating or temperature distribution within food samples (three different carrot and one radish rectangles) placed vertically and horizontally within a radio frequency heating cavity. The intensity of the electric field in radio frequency was found to be symmetrical. The temperatures at the vertically top positions were lower than the vertically bottom positions at the equidistance from the vertical center with the highest was at the vertically central position. The rate of temperature rise at all the positions were higher in taller (higher mass) than the shorter (lower mass) rectangles of carrots. The temperatures at the corners and edges were lower than at the cross sectionally central positions at all the heights tested in both carrots and radishes. The rate of temperature rise at all the vertical positions was higher in radish rectangles than in the carrot rectangles of the same dimensions. The similarity of temperature distribution in carrot and radish rectangles suggested that the heating patterns and uniformity in carrots and radishes in RF heating were almost the same.

Use of Analytical Expressions of Convection in Conjugated Heat Transfer Problems

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
R. Karvinen
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Flow Direction ◽  
Superposition Principle ◽  
Industrial Applications ◽  
Transfer Coefficients ◽  
Flat Plates ◽  
Surface Temperature Distribution ◽  
Analytical Expressions

The heat transfer coefficient of convection from the wall to the flow depends on flow type, on surface temperature distribution in a stream-wise direction, and in transient cases also on time. In so-called conjugated problems, the surface temperature distribution of the wall and flow are coupled together. Thus, the simultaneous solution of convection between the flow and wall, and conduction in the wall are required because heat transfer coefficients are not known. For external and internal flows, very accurate approximate analytical expressions have been derived for heat transfer in different kinds of boundary conditions which change in flow direction. Due to the linearity of the energy equation, the superposition principle can be adopted to couple with these expressions the surface temperature and heat flux distributions in conjugated problems. In the paper, this type of approach is adopted and applied to a number of industrial applications ranging from flat plates of electroluminecence displays to the optimization of heat transfer in fins, fin arrays and mobile phones.

AN IMPROVED LATTICE KINETIC SCHEME FOR INCOMPRESSIBLE VISCOUS FLUID FLOWS

2013 ◽  
Vol 25 (01) ◽  
pp. 1340017 ◽  
Author(s):  
KOSUKE SUZUKI ◽  
TAKAJI INAMURO
Keyword(s):  
Stokes Equations ◽  
Fluid Flows ◽  
Kinetic Scheme ◽  
Navier Stokes ◽  
Test Problems ◽  
Navier Stokes Equations ◽  
Artificial Compressibility ◽  
The Poisson Equation ◽  
Iterative Calculation ◽  
Boltzmann Method

The lattice Boltzmann method (LBM) is an explicit numerical scheme for the incompressible Navier–Stokes equations (INSE) without integrating the Poisson equation for the pressure. In spite of its merit, the LBM has some drawbacks in accuracy. First, we review drawbacks for three numerical methods based on the LBM. The three methods are the LBM with the Bhatnagar–Gross–Krook model (LBGK), the lattice kinetic scheme (LKS) and the link-wise artificial compressibility method (LWACM). Second, in order to remedy the drawbacks, we propose an improved LKS. The present method incorporates (i) the scheme used in the LWACM for determining the kinematic viscosity, (ii) an iterative calculation of the pressure and (iii) a semi-implicit algorithm, while preserving the simplicity of the algorithm of the original LKS. Finally, in simulations of test problems, we find that the improved LKS eliminates the drawbacks and gives more accurate and stable results than LBGK, LKS and LWACM.

Computation of Lattice Kinetic Scheme for Double-Sided Parallel and Antiparallel Wall Motion

2014 ◽  
Vol 592-594 ◽  
pp. 1967-1971 ◽  
Author(s):  
D. Arumuga Perumal ◽  
Anoop K. Dass
Keyword(s):  
Lattice Boltzmann ◽  
Wall Motion ◽  
Kinetic Scheme ◽  
Reynolds Numbers ◽  
Uniform Lattice ◽  
Driven Cavity ◽  
Aspect Ratios ◽  
Lattice Arrangement ◽  
Steady Solutions ◽  
Boltzmann Method

This paper is concerned with the double-sided lid-driven cavity simulation of two-dimensional lattice kinetic scheme on the uniform lattice arrangement based on the standard lattice Boltzmann method. The double-sided lid-driven cavity problem has multiple steady solutions for some aspect ratios. However, for the double-sided square cavity no multiplicity of solutions has been observed for both the parallel and antiparallel motion of the walls. To validate this new lattice kinetic scheme, the numerical simulations of the double-sided square driven cavity flow at Reynolds numbers from 10 to 1000 are carried out. The Reynolds number effect on the flow structure is clearly manifested by the streamline patterns and velocity profiles. It is concluded that the present study in double-sided lid-driven cavity produces results that are in excellent conformity with earlier conventional numerical observations.

Sign in / Sign up

Export Citation Format

Share Document