Development of a Heat-Balance Model for a Fluidized Bed Waste Gasification Furnace

2004 ◽  
Vol 30 (4) ◽  
pp. 447-454
Author(s):  
Takahiro MARUMOTO ◽  
Naoki FUJIWARA ◽  
Noriyuki OHYATSU ◽  
Tetsuya IWASE
Keyword(s):  
Fluidized Bed ◽  
Heat Balance ◽  
Balance Model ◽  
Waste Gasification

The Local Heat Balance in a Stationary Fluidized-Bed Furnace Burning Biomass Fuels

2003 ◽  
Author(s):  
Fredrik Niklasson ◽  
Filip Johnsson
Keyword(s):  
Fluidized Bed ◽  
Combustion Rate ◽  
Heat Balance ◽  
Circulating Fluidized Bed ◽  
Local Heat ◽  
Splash Zone ◽  
Two Phase ◽  
Bed Temperature ◽  
Temperature Constant ◽  
The Vertical Distribution

This work investigates the influence of biomass fuel properties on the local heat balance in a commercial-scale fluidized bed furnace. Experiments with different wood based fuels were performed in the Chalmers 12 MWth circulating fluidized bed boiler, temporarily modified to run under stationary conditions. A two-phase flow model of the bed and splash zone is applied, where the combustion rate in the bed is estimated by global kinetic expressions, limited by gas exchange between oxygen-rich bubbles and a fuel-rich emulsion phase. The outflow of bubbles from the bed is treated as “ghost bubbles” in the splash zone, where the combustion rate is determined from turbulent properties. It is found that a large amount of heat is required for the fuel and air to reach the temperature of the bed, in which the heat from combustion is limited by a low char content of the fuel. This implies that a substantial fraction of the heat from combustion of volatiles in the splash zone has to be transferred back to the bed to keep the bed temperature constant. It is concluded that the moisture content of the fuel does not considerably alter the vertical distribution of heat emitted, as long as the bed temperature is kept constant by means of flue gas recycling.

Heat balance model for a human body in the form of wet bulb globe temperature indices

2018 ◽  
Vol 71 ◽  
pp. 1-9 ◽  
Author(s):  
Tomonori Sakoi ◽  
Tohru Mochida ◽  
Yoshihito Kurazumi ◽  
Kohei Kuwabara ◽  
Yosuke Horiba ◽  
...  
Keyword(s):  
Human Body ◽  
Heat Balance ◽  
Balance Model ◽  
Wet Bulb Globe Temperature ◽  
Temperature Indices ◽  
Globe Temperature

scholarly journals The human heat balance in the city of Novi Sad (Serbia)

2012 ◽  
Vol 92 (4) ◽  
pp. 99-112
Author(s):  
Aleksandar Krajic
Keyword(s):  
Heat Exchange ◽  
Heat Balance ◽  
Meteorological Data ◽  
Balance Model ◽  
Human Organism ◽  
Health Resource ◽  
Weather Variables ◽  
Climatological Station ◽  
Novi Sad ◽  
The City

This analysis is based on the human heat balance according to the bioclimatic man-environment heat exchange model created by Krzysztof B?a?ejczyk. The final result of the human heat balance model points to biothermal weather situations for the outdoor recreational needs. In this analysis, middles daily meteorological data (of climatological station of Novi Sad) were used for two extreme months, January and July. In this work, it is analyzed two periods, the first is for 1992-2010. and the second is for year 2010. The aim is to show how weather can be evaluated for recreational needs which the health resource of Novi Sad and to point out the shortcomings when it comes to multi-year analysis. The objective of this article has been to present a bioclimatic analysis of city Novi Sad and how weather variables come together in order to give a climate meaning on human organism.

scholarly journals CFD-PBM Coupled Simulation of Liquid-Liquid Dispersions in Spray Fluidized Bed Extractor: Comparison of Three Numerical Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Dan Zheng ◽  
Wei Zou ◽  
Chuanfeng Peng ◽  
Yuhang Fu ◽  
Jie Yan ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Method Of Moments ◽  
Chemical Engineering ◽  
High Reliability ◽  
Scale Up ◽  
Population Balance ◽  
Numerical Code ◽  
Balance Model ◽  
Quadrature Method ◽  
Quadrature Method Of Moments

A coupled numerical code of the Euler-Euler model and the population balance model (PBM) of the liquid-liquid dispersions in a spray fluidized bed extractor (SFBE) has been performed to investigate the hydrodynamic behavior. A classes method (CM) and two representatively numerical moment-based methods, namely, a quadrature method of moments (QMOM) and a direct quadrature method of moments (DQMOM), are used to solve the PBE for evaluating the effect of the numerical method. The purpose of this article is to compare the results achieved by three methods for solving population balance during liquid-liquid two-phase mixing in a SFBE. The predicted results reveal that the CM has the advantage of computing the droplet size distribution (DSD) directly, but it is computationally expensive if a large number of intervals are needed. The MOMs (QMOM and DQMOM) are preferable to coupling the PBE solution with CFD codes for liquid-liquid dispersions simulations due to their easy application, reasonable accuracy, and high reliability. Comparative results demonstrated the suitability of the DQMOM for modeling the spray fluidized bed extractor with simultaneous droplet breakage and aggregation. This work increases the understanding of the chemical engineering characteristics of multiphase systems and provides a theoretical basis for the quantitative design, scale-up, and optimization of multiphase devices.

Modelling the effect of heat stress on food intake, heat production and growth in pigs

2004 ◽  
Vol 79 (1) ◽  
pp. 135-148 ◽  
Author(s):  
F. B. Fialho ◽  
J. van Milgen ◽  
J. Noblet ◽  
N. Quiniou
Keyword(s):  
Heat Stress ◽  
Food Intake ◽  
Heat Balance ◽  
Effective Means ◽  
Calibration Procedure ◽  
Balance Model ◽  
Data Sets ◽  
Hot Environment ◽  
Metabolism Model

Abstract A heat balance model was combined with a food intake model and a metabolism model, to form a larger model which estimates a pig’s response to heat stress. The combined model was implemented as a computer program, and used to calibrate, test and validate parts of the heat balance model. Heat transfer modes considered were convection, radiation and evaporation of water at the skin, and heating and humidification of air by breathing. Sensitivity analysis revealed a large effect of air temperature, humidity and velocity on heat loss, especially in a hot environment. It also showed that wetting of the pig’s skin is the most effective means to alleviate heat stress. The calibration procedure confirmed that characteristics related to heat tolerance in pigs must be re-evaluated, due mainly to the changes brought about by genetic improvement (such as reduced backfat thickness). The model was challenged using two different data sets. Although simulated results varied in the same way as measured data, more research is needed to determine more precisely some of the parameters. Long-term predictions were more reliable than those for short (1-day) periods.

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