The Calculation of Furnace-Flow Properties and Their Experimental Verification

1976 ◽  
Vol 98 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P. Hutchinson ◽  
E. E. Khalil ◽  
J. H. Whitelaw ◽  
G. Wigley
Keyword(s):  
Heat Flux ◽  
Experimental Verification ◽  
Reaction Model ◽  
Isothermal Flow ◽  
Calculation Procedure ◽  
Combustion Model ◽  
Flow Properties ◽  
Swirl Number ◽  
Flux Measurements ◽  
One Step

Measurements of mean axial velocity, and the corresponding normal stress are reported for the isothermal flow of air and for a combusting mixture of natural gas in an axisymmetric furnace enclosure with a coaxial burner. Temperature and wall heat flux measurements were also obtained for the combusting flow. The swirl number of the flow was 0.5. The measurements are compared with the results of a calculation procedure incorporating a two equation turbulence model and a one step reaction model. The combustion model allowed fuel and oxygen to coexist at the same place but not at the same time. The comparison indicates that the calculation procedure qualitatively represents the measurements but that quantitative differences exist. The argument is sufficiently close, however, to justify the use of the method for some design purposes.

QUANTIFYING ERRORS IN HEAT FLUX MEASUREMENTS USING A VERTICAL SEQUENCE OF THERMOCOUPLE SENSORS

2016 ◽  
Author(s):  
Gabriela Villegas ◽  
◽  
Jerry P. Fairley ◽  
Cary R. Lindsey ◽  
Megan M. Aunan ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flux Measurements

Fast-Response transient heat flux measurements in a plasma wind tunnel

2021 ◽  
Vol 173 ◽  
pp. 121234
Author(s):  
Byrenn Birch ◽  
David Buttsworth ◽  
Stefan Löhle ◽  
Fabian Hufgard
Keyword(s):  
Heat Flux ◽  
Wind Tunnel ◽  
Fast Response ◽  
Flux Measurements ◽  
Transient Heat Flux

An analog period method for gap‐filling of latent heat flux measurements

2021 ◽  
Author(s):  
Lucas Emilio B. Hoeltgebaum ◽  
Nelson Luís Dias ◽  
Marcelo Azevedo Costa
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Gap Filling ◽  
Flux Measurements

Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

2017 ◽  
Vol 899 ◽  
pp. 173-178 ◽  
Author(s):  
Ronydes Batista Jr. ◽  
Bruna Sene Alves Araújo ◽  
Pedro Ivo Brandão e Melo Franco ◽  
Beatriz Cristina Silvério ◽  
Sandra Cristina Danta ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Large Scale ◽  
Catalytic Pyrolysis ◽  
Petroleum Products ◽  
Reaction Model ◽  
Heating Rates ◽  
Coffee Grounds ◽  
One Step ◽  
Global Reaction ◽  
The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

Model-based optimization of equipment and control for heat flux measurements in a laboratory fermentor

1995 ◽  
Vol 11 (5) ◽  
pp. 525-532 ◽  
Author(s):  
Bastiaan H. A. van Kleeff ◽  
J. Gijs Kuenen ◽  
Ger Honderd ◽  
Sef J. Heijnen
Keyword(s):  
Heat Flux ◽  
Model Based ◽  
Flux Measurements ◽  
And Control ◽  
Laboratory Fermentor

Experimental and Numerical Investigation of a Large Cylindrical Oil-Fired Combustor

1983 ◽  
Author(s):  
F. M. ElMahallawy ◽  
E. E. Khalil ◽  
O. Abdel Aal
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Gas Phase ◽  
Combustion Model ◽  
Steam Boiler ◽  
Discrete Ordinate ◽  
Radiation Model ◽  
Droplet Motion ◽  
Transfer Rates ◽  
Lagrangian Equations

The present work presents measurements of velocity, temperature and heat transfer rates carried out on a segmented water-cooled cylindrical oil-fired flame tube typical of a 0.56 kg/s packaged fire-tube steam boiler. A prediction procedure, that solves the conservation equations of the various entities, was successfully used to produce computed velocities, temperatures and heat flux distributions. A two-equation turbulence model, a combustion model and a discrete ordinate radiation model were used to approximate the various characteristics of the flow. The combustion model solved the Eulerian equations of the gas phase, and the Lagrangian equations of the droplet motion, heating, evaporation and combustion.

Ice-Giants Net Flux Radiometer for Heat Flux Measurements

2021 ◽  
Author(s):  
Shahid Aslam ◽  
Simon Calcutt ◽  
Nicolas Gorius ◽  
Patrick Irwin ◽  
George Nehmetallah ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flux Measurements ◽  
Net Flux

scholarly journals The impact of broadleaved woodland on water resources in lowland UK: II. Evaporation estimates from sensible heat flux measurements over beech woodland and grass on chalk sites in Hampshire

2005 ◽  
Vol 9 (6) ◽  
pp. 607-613 ◽  
Author(s):  
J. Roberts ◽  
P. Rosier ◽  
D. M. Smith
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Excellent Agreement ◽  
Sensible Heat Flux ◽  
Late Summer ◽  
Eddy Correlation ◽  
Sensible Heat ◽  
Flux Measurements ◽  
Shallow Soils ◽  
The Impact

Abstract. The impact on recharge to the Chalk aquifer of substitution of broadleaved woodland for pasture is a matter of concern in the UK. Hence, measurements of energy balance components were made above beech woodland and above pasture, both growing on shallow soils over chalk in Hampshire. Latent heat flux (evaporation) was calculated as the residual from these measurements of energy balances in which sensible heat flux was measured with an eddy correlation instrument that determined fast response vertical wind speeds and associated temperature changes. Assessment of wind turbulence statistics confirmed that the eddy correlation device performed satisfactorily in both wet and dry conditions. There was excellent agreement between forest transpiration measurements made by eddy correlation and stand level tree transpiration measured with sap flow devices. Over the period of the measurements, from March 1999 to late summer 2000, changes in soil water content were small and grassland evaporation and transpiration estimated from energy balance-eddy flux measurements were in excellent agreement with Penman estimates of potential evaporation. Over the 18-month measurement period, the cumulative difference between broadleaved woodland and grassland was small but evaporation from the grassland was 3% higher than that from the woodland. In the springs of 1999 and 2000, evaporation from the grassland was greater than that from the woodland. However, following leaf emergence in the woodland, the difference in cumulative evaporation diminished until the following spring.

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