scholarly journals Modeling for Pyrolysis of Solid Biomass

2019 ◽  
Vol 64 (2) ◽  
pp. 192-204
Author(s):  
Biljana Miljkovic ◽  
Branislava Nikolovski ◽  
Dejan Mitrović ◽  
Jelena Janevski
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Weight Loss ◽  
Degradation Mechanism ◽  
Volatile Matter ◽  
Point Of View ◽  
Experimental Results ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Simulation Results

In comparison to coal, biomass is characterized by a higher content of volatile matter. It is a renewable source of energy which has many advantages from an ecological point of view. Understanding the physical phenomena of pyrolysis and representing them with a mathematical model is the primary step in the design of pyrolysis reactors. In the present study, an existing mathematical model is used to describe the pyrolysis of a single solid particle of biomass. It couples the heat transfer equations with the chemical kinetics equations. A finite difference method is used for solving the heat transfer equation and the two-step pyrolysis kinetics equations. The model equation is solved for a slab particle of equivalent dimension 0.001 m and temperature ranging from 300 to 923 K. An original numerical model for the pyrolysis of wood chips is proposed and relevant equations solved using original program realized in MATLAB.To check the validity of the numerical results, experimental results of pyrolysis of woody biomass in laboratory facility was used. The samples were heated over a range of temperature from 300 to 923 K with three different heating rates of 21, 32 and 55 K/min, and the weight loss was measured. The simulation results as well as the results obtained from thermal decomposition process indicate that the temperature peaks at maximum weight loss rate change with the increase in heating rate. The experimental results showed that the simulation results are in good agreement and can be successfully used to understand the degradation mechanism of solid reaction.

Mathematical Simulation of Flux Film State in Gap between Mould and Solidified Shell

2017 ◽  
Vol 893 ◽  
pp. 272-275
Author(s):  
Li Jun Cao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Slab Surface ◽  
Slab Caster ◽  
Mould Flux ◽  
Main Factors ◽  
Simulation Results ◽  
The Mathematical Model ◽  
Casting Production ◽  
Film State

The mathematical model for heat transfer during solidification of steel in the mould of slab caster was established in this paper. The temperature distribution of slab surface was described. Based on the work which was described above, the model of flux film state was developed in present paper. Lubrication function of mould flux and the effects of main factors on lubrication had been discussed. The simulation results provided theory foundation for appraising lubrication function of flux and optimizing casting production.

Dropwise Evaporation

1979 ◽  
Vol 101 (3) ◽  
pp. 441-446 ◽  
Author(s):  
C. Bonacina ◽  
S. Del Giudice ◽  
G. Comini
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Specific Heat ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Technical Process ◽  
Experimental Apparatus ◽  
Mist Cooling ◽  
Transfer Mechanisms ◽  
Very High

Evaporation of atomized liquids on hot surfaces is identified as an interesting technical process, characterized by very high values of specific heat fluxes. An experimental apparatus, expressely built for the evaluation of heat transfer mechanisms in mist cooling with low excess temperatures, is described. A mathematical model, based on the assumption of dropwise evaporation, is used to correlate the experimental results.

Experimental Investigation Into Thermal Siphon Used as an Intermediate Circuit of an Integrated Cooling System Reactor

2002 ◽  
Author(s):  
L. A. Adamovich ◽  
B. A. Gabaraev ◽  
S. L. Solovjev ◽  
S. B. Shpansky
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Experimental Investigation ◽  
Cooling System ◽  
Experimental Results ◽  
Power Transfer ◽  
Test Rig ◽  
Heat Transfer Capacity ◽  
Intermediate Circuit

In the paper the results of study in heat transfer capacity of the themosyphon mock-up which is considered as an intermediate circuit of the reactor under design, are presented. The mock-up design, the test rig and the experimental results are described. It is shown that the simplest mathematical model describes the processes of power transfer by the thermosyphon under certain conditions.

Steady-State Operation Analysis for a Three-Winding Single-Phase Capacitor Motor

2015 ◽  
Vol 713-715 ◽  
pp. 1027-1030
Author(s):  
Jin Hui Zeng ◽  
Jian Guo Deng
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Power Supply ◽  
Single Phase ◽  
Experimental Results ◽  
Calculation Formula ◽  
Voltage Unbalance ◽  
Operation Analysis ◽  
Steady State Operation ◽  
Simulation Results

The steady-state mathematical model of Smith-connection three-winding single-phase capacitor motor is established, and the capacitance calculation formula in minimum voltage unbalance condition is deduce .Based on this, by MATLAB simulated program, a operation simulation of Smith single phase capacitor motor that in single-phase 220V power supply and in single-phase 380V power supply is developed. The simulation results agree with the experimental results.

Heat Transfer Investigation of an Additively Manufactured Minichannel Heat Exchanger

2019 ◽  
Author(s):  
Hamidreza Rastan ◽  
Amir Abdi ◽  
Monika Ignatowicz ◽  
Bejan Hamawandi ◽  
Poh Seng Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Single Phase ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Working Fluid ◽  
Minichannel Heat Exchanger ◽  
Simulation Results ◽  
Good Agreement

Abstract This study investigates the thermal performance of laminar single-phase flow in an additively manufactured minichannel heat exchanger both experimentally and numerically. Distilled water was employed as the working fluid, and the minichannel heat exchanger was made from aluminum alloy (AlSi10Mg) through direct metal laser sintering (DMLS). The minichannel was designed with a hydraulic diameter of 2.86 mm. The Reynolds number ranged from 175 to 1360, and the heat exchanger was tested under two different heat fluxes of 1.5 kWm−2 and 3 kWm−2. A detailed experiment was conducted to obtain the thermal properties of AlSi10Mg. Furthermore, the heat transfer characteristics of the minichannel heat exchanger was analyzed numerically by solving a three-dimensional conjugate heat transfer using the COMSOL Multiphysics® to verify the experimental results. The experimental results were also compared to widely accepted correlations in literature. It is found that 95% and 79% of the experimental data are within ±10% range of both the simulation results and the values from the existing correlations, respectively. Hence, the good agreement found between the experimental and simulation results highlights the possibility of the DMLS technique as a promising method for manufacturing future multiport minichannel heat exchangers.

scholarly journals Investigation of pyrolysis kinetics parameters and thermal behavior of thermochemically modified bagasse for bioenergy potential

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Christiano Bruneli Peres ◽  
André Henrique Rosa ◽  
Leandro Cardoso de Morais
Keyword(s):  
Sugarcane Bagasse ◽  
Volatile Matter ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Kinetics Parameters ◽  
Exponential Factor ◽  
Other Substances ◽  
Textural Parameters ◽  
Three Stages ◽  
Morphological Differences

AbstractBiomass is considering a source of organic carbon, which can replace fossil resources by using pyrolysis process, therefore an efficient biomass thermal modification technology has been target of so much research. The objective of this work is to study the potential energy of sugarcane bagasse and thermochemically modified bagasse for bioenergy potential for use in heat generation and energy. The thermal analysis was conducted by powder-shaped exposure of the three study samples (SB, AC-1, and AC-2) at three heating rates of (5, 7.5 and 10 °C min−1), it was possible to identify three stages of thermal degradation and study some thermochemical reactions, using two iso-conversional models, Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) to calculate some kinetic parameters, such as activation energy (Ea) and pre-exponential factor (A). First step was about the devolatilization of volatile matter, moisture, and other substances. Degradation of hemicellulose, cellulose and lignin were shown in a second step. Characterization analyzes, such as SEM–EDX and textural parameters of the samples, show the presence of carbon in samples SB and AC-1. Due to SEM analyzes, morphological differences between the samples are showing as AC-1 and AC-2 samples present a rougher shape with pores, on the other hand, SB sample show a fibrous shape. In conclusion, sugarcane bagasse and thermochemically modified bagasse, show very promising results, for future studies, such as for bioenergy potential.

scholarly journals EXPERIMENTAL STUDIES OF HEAT EXCHANGE DURING WATER COOLING AND STEAM CONDENSATION IN DEMOVER RADIATOR SECTIONS

2021 ◽  
Vol 1 (38) ◽  
pp. 107-114
Author(s):  
V. Mogila ◽  
M. Kovtanets ◽  
M. Morneva
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Mathematical Model ◽  
Cooling System ◽  
Experimental Studies ◽  
Road Transport ◽  
Thermal Calculation ◽  
Mode Of Operation ◽  
Simulation Results ◽  
The Mathematical Model

The Department of Railwayand Road Transport, lift and care system of Volodymyr Dahl East Ukrainian National University, an energy-saving cooling system for diesel locomotives using phase transitions of the coolant has been developed. The proposed cooling system allows to maintain constant optimal temperatures of cooling objects at ambient temperatures ± 40 ºC and in any mode of operation of the diesel engine. For thermal calculation of the radiator section operating in the mode of the steam condenser, the mathematical model of process of heat transfer from steam to walls of a flat tube at condensation is developed that considers geometrical features of section of a tube. The adequacy of this mathematical model is verified by comparing the simulation results with the obtained experimental data. During the tests, the outlet water temperature, inlet and outlet air temperature, and air pressure in front of and behind the radiator were measured. Having the values of wall temperature, steam temperature and condensate, knowing the value of steam consumption and the experimental heat transfer coefficient, it becomes possible to verify the adequacy of the mathematical model by comparing the simulation results with the obtained experimental data. Schemes of bench equipment, test methods, experimental planning and basic calculation dependences required for testing serial radiator sections of a locomotive in the standard mode of operation and in the mode of steam condensers are presented.

scholarly journals A MATHEMATICAL MODEL OF GALVANIC CORROSION UNDER THE CONDITIONS OF A THIN ELECTROLYTE FILM

2016 ◽  
Vol 56 (2) ◽  
pp. 106-111
Author(s):  
Vít Jeníček ◽  
Linda Diblíková
Keyword(s):  
Mathematical Model ◽  
Weight Loss ◽  
Time Dependence ◽  
Experimental Error ◽  
Atmospheric Corrosion ◽  
Galvanic Corrosion ◽  
Experimental Results ◽  
Polarization Curves ◽  
Electrolyte Film ◽  
The Difference

<p>A mathematical model of galvanic corrosion under the conditions of a thin electrolyte film was used to evaluate atmospheric corrosion. Experimentally determined weight loss values were used to validate the modelled results. The time dependence of the corrosion degradation was included in the model using polarization curves of the corroded materials. The difference between the modelled results and the experimental results was 20%, taking the experimental error into account.</p>

A Study on the Modelling and Simulation of Part Motion in Vibratory Feeding

2010 ◽  
Vol 34-35 ◽  
pp. 2006-2010
Author(s):  
L. Han ◽  
J.X. Gao
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Modelling And Simulation ◽  
Experimental Results ◽  
Feeding System ◽  
Assembly Automation ◽  
Simulation Results ◽  
Part Motion ◽  
Vibratory Feeding

It is known that vibratory feeders are the most versatile of all hopper feeding devices for small engineering parts and play a key role in assembly automation. This work develops a mathematical model of the part motion in vibratory feeding, from which how the part works can be better known. A computer simulation programmed with MATLAB has been made to predict the conveying velocity of the parts in vibration feeding system, and furthermore, experiments have been carried out for verification purpose. The experimental results show that the simulation results are reasonable, and hence can be used to improve the design of vibratory feeding system.

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