scholarly journals The Temperature Profile of Rectangular Fuel Source Jet Fire with Different Aspect Ratio

2018 ◽  
Vol 211 ◽  
pp. 280-287
Author(s):  
You-bo Huang ◽  
Yan-feng Li ◽  
Bing-yan Dong
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Fuel Source

scholarly journals Spanwise Transport in Axial-Flow Turbines: Part 2 — Throughflow Calculations Including Spanwise Transport

1993 ◽  
Author(s):  
K. L. Lewis
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Low Aspect Ratio ◽  
Loss Distributions ◽  
Diffusive Term ◽  
Two Stages ◽  
Throughflow Model

In Part 1 of this paper, a repeating stage condition was shown to occur in two low aspect ratio turbines, after typically two stages. Both turbulent diffusion and convective mechanisms were responsible for spanwise transport. In this part, two scaling expressions are determined that account for the influence of these mechanisms in effecting spanwise transport. These are incorporated into a throughflow model using a diffusive term. The inclusion of spanwise transport allows the use of more realistic loss distributions by the designer as input to the throughflow model and therefore focuses attention on areas where losses are generated. In addition, modelling of spanwise transport is shown to be crucial in predicting the attenuation of a temperature profile through a turbine.

Investigating the Potential of Recycling Flare-Source Hydrocarbon Gases in an Industrial Burner

2021 ◽  
pp. 1-35
Author(s):  
Fahd M. Mohamed ◽  
Fadwa T. Eljack ◽  
Samer F. Ahmed ◽  
Saud Ghani
Keyword(s):  
Temperature Profile ◽  
Environmental Concern ◽  
Flame Temperature ◽  
Hydrocarbon Fuel ◽  
Economic Loss ◽  
Hydrocarbon Gases ◽  
Ansys Fluent ◽  
Linear Effect ◽  
Fuel Feed ◽  
Fuel Source

Abstract Flare gas is considered a global environmental concern. Flaring contributes to wasting limited material and energy resources, economic loss and greenhouse gas emissions. Utilizing flared gas as fuel feed to industrial cracking furnaces grants advantages in terms of fuel economy and emissions reduction. This work presents the results obtained by ANSYS fluent simulation of a flare hydrocarbon gas utilized in a steam cracking furnace of ethylene process when combusting hydrocarbons flare gas in a low NOx burner. In addition, the study determined the suitability of different hydrocarbon fuel mixtures in satisfying the required adiabatic flame temperature. The flared stream is assumed to be inlet from both primary and secondary staged fuel burners. The simulation results illustrated the detailed temperature profiles along the furnace flue gas side. They also presented the influence of flare stream compositions and Wobbe Index (WI) on the temperature profile. It was found that having an alternative fuel with a heating value or WI similar to that of methane would not result in the same temperature profile of methane, as a current fuel source. In addition, using different excess air percentages has no linear effect on the burner’s temperature profile. However, the results showed that the best replacement of methane, as the main fuel source, is a flare mixture with the same WI of methane as well as a certain H2 content needs to be added to every flare mixture composition to reach the same temperature profile of methane

Temperature Profile of Thermal Impinging Flow Induced by Horizontally Oriented Rectangular Jet Flame Upon an Opposite Plate

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Bingyan Dong ◽  
Youbo Huang ◽  
Jinxiang Wu
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Vertical Temperature ◽  
Jet Flame ◽  
Opposite Wall ◽  
Aspect Ratios ◽  
Fuel Jet ◽  
Jet Velocity ◽  
Jet Velocities ◽  
Impinging Flow

The horizontally oriented jet flame induced by rectangular source impinging upon the opposite wall is actually common in the chemical industry, but the related studies are limited. In this paper, the computational fluid dynamics codes are carried out to investigate the temperature profile in thermal impinging flow of the horizontally oriented methane jet flame with rectangular source, which the rectangular orifice is 400 mm2 with three different aspect ratios (L/W = 1, 2, 4); besides, the jet velocities vary from 27.5 m/s to 125 m/s. As the horizontally oriented methane jet flame impinges on the vertical plate in front of the fuel orifice directly, the vertical temperature along the opposite plate is focused on. Results show that the temperature near the impingement point is the same for different jet velocities, but the temperature along the vertical direction is larger with increasing fuel jet velocity. Moreover, the orifice aspect ratio has a significant effect on the temperature, which increases with the aspect ratio at a given position for the momentum-controlled flame. The effective heat release rate on the basis of unburned fuel and ellipse flame shape hypothesis is put forward to correlate the temperature profile. Finally, a new correlation to illustrate the vertical temperature rising along the opposite plate is proposed in light of the orifice aspect ratio and fuel jet velocity, and the predictions obtained by the proposed model agree well with the numerical results, which is applicable for the horizontally oriented flame with rectangular source impinging upon the opposite wall.

Spanwise Transport in Axial-Flow Turbines: Part 2—Throughflow Calculations Including Spanwise Transport

1994 ◽  
Vol 116 (2) ◽  
pp. 187-193 ◽  
Author(s):  
K. L. Lewis
Keyword(s):  
Aspect Ratio ◽  
Temperature Profile ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Low Aspect Ratio ◽  
Loss Distributions ◽  
Diffusive Term ◽  
Two Stages ◽  
Throughflow Model

In Part 1 of this paper, a repeating stage condition was shown to occur in two low aspect ratio turbines, typically after two stages. Both turbulent diffusion and convective mechanisms were responsible for spanwise transport. In this part, two scaling expressions are determined that account for the influence of these mechanisms in effecting spanwise transport. These are incorporated into a throughflow model using a diffusive term. The inclusion of spanwise transport allows the use of more realistic loss distributions by the designer as input to the throughflow model and therefore focuses attention on areas where losses are generated. In addition, modeling of spanwise transport is shown to be crucial in predicting the attenuation of a temperature profile through a turbine.

scholarly journals Experimental production of charcoal morphologies to discriminate fuel source and fire type in the Siberian taiga

2021 ◽  
Author(s):  
Angelica Feurdean
Keyword(s):  
Aspect Ratio ◽  
High Intensity ◽  
Plant Evolution ◽  
Effect Of Temperature ◽  
Experimental Production ◽  
Charcoal Production ◽  
Surface Fires ◽  
Aspect Ratios ◽  
Fuel Source ◽  
Fire Type

Abstract. The analysis of charcoal fragments in peat and lake sediments is the most widely used approach to reconstruct past biomass burning. With a few exceptions, this method typically relies on the quantification of the total charcoal content of the sediment. To enhance charcoal analyses for the reconstruction of past fire regimes, and to make the method more relevant to studies of both plant evolution and fire management, more information must be extracted from charcoal particles. Here, I burned in the laboratory seven fuel types comprising 17 species from boreal Siberia, and build on published schemes to develop morphometric and finer diagnostic classifications of the experimentally charred particles. As most of the species used in this study are common to Northern Hemisphere forests and peatlands, these results can be directly applicable over a broad geographical scale. Results show that the effect of temperature on charcoal production is fuel dependent. Graminoids and Sphagnum, and wood (trunk) lose the most mass at low burn temperatures, whereas heathland shrub leaves, brown moss, and ferns retain the most mass at high burn temperatures. In contrast to the wood of trunk, the wood of twigs retained their mass at intermediate temperature. This suggests that species with low mass retention at hotter burning temperatures might be underrepresented in the fossil charcoal record. Charred particle aspect ratio (L / W) appeared to be the strongest indicator of the fuel type burnt. Graminoid charcoals are more elongate than those of all other fuel types, leaf charcoals are the shortest and bulkiest, and twig and wood charcoals are intermediate. Finer diagnostic features were the most useful in distinguishing between wood, graminoid, and leaf particles, but further distinctions within these fuel types are difficult. High-aspect-ratio particles dominated by graminoid and Sphagnum morphologies are robust indicators of cooler surface fires. Contrastingly, abundant wood and leaf morphologies and low-aspect-ratio particles likely indicate higher-temperature fires. However, the overlapping morphologies of leaves and wood from trees and shrubs make it hard to distinguish between high-intensity surface fires combusting living shrubs and dead wood and leaves or high-intensity crown fires combusting living trees. Despite these limitations, the combined use of charred-particle aspect ratios and fuel morphotypes can aid in more robustly interpreting changes in fuel source and fire type, thereby substantially refining histories of past wildfires. Further fields of investigation to improve the interpretation of the fossil charcoal records will require: i) More in-depth knowledge of plant anatomy for a better determination of fuel sources; ii) Relate the proportion of particular charcoal morphotypes to the quantity of biomass; iii) Link the chemical composition of fuels, combustion temperature, and charcoal production. The advanced use of image-recognition software to collect data on other charcoal features could also aid in extracting fire temperatures as well as a change in particles morphology and morphometry during particles transportation.

Heat Transfer in Packed Bed Elliptic-Cylindrical Reactor: The Geometry Effect

2019 ◽  
Vol 391 ◽  
pp. 54-59 ◽  
Author(s):  
R. Moura da Silva ◽  
A. Santos Pereira ◽  
A.G. Barbosa de Lima ◽  
Morgana Vasconcellos Araújo ◽  
R.S. Santos
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Temperature Profile ◽  
Fixed Bed ◽  
Three Dimensional ◽  
Packed Bed ◽  
Dimensionless Temperature ◽  
Variable Porosity ◽  
Cylindrical Reactor ◽  
Half Axis

This work aims to develop a transient three-dimensional mathematical model to predict the temperature distribution in a fixed-bed elliptical cylindrical reactor to different geometric aspect ratio (L2/L1=1.5, 2.0 and 3.0). The model considers variable thermo-physical properties, a flat temperature profile at the fluid inlet, as well as a variable porosity model. The governing equation is solved using the finite volume method, coupled with WUDS interpolation scheme and fully implicit method. Results of the temperature profile along the reactor are presented and discussed at different times. As results, it was found that the maximum rate of heat transfer within the reactor occurs near the minor half-axis region of the ellipse (cross-section area of the reactor) and it intensifies over time and that the dimensionless temperature profile is practically unchanged with the aspect ratio.

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