Premixing and Flash Vaporization in a Two-Stage Combustor

1982 ◽  
Vol 104 (1) ◽  
pp. 36-43 ◽  
Author(s):  
B. G. A. Sjo¨blom

A double recirculation zone two-stage combustor fitted with airblast atomizers has been investigated in a previous work. The present paper describes further tests with premixing tubes in the secondary combustion zone. Flash vaporization was employed to ensure complete vaporization of the secondary fuel, which was heated to 600K by the combustor inlet air. The combustor was run at conditions corresponding to four different engine power settings, and the effect of primary/secondary fuel flow split on emissions was investigated. Tests were also performed with unheated secondary fuel, and comparisons were made with flash vaporization data. The best configuration reduced the oxides of nitrogen by 54 percent, carbon monoxide by 59 percent and unburned hydrocarbons by 97 percent as compared to emission levels for the standard JT8D combustor, which was used as a reference.

Author(s):  
G. J. Sturgess ◽  
R. McKinney ◽  
S. Morford

Measurements of the emissions from an experimental engine were analyzed to construct a design chart for the reduction of oxides of nitrogen (NOx) in conventional combustors. The design chart was used to reconfigure the stoichiometry distribution of the combustor of a production engine so as to reduce NOx while holding the emissions of carbon monoxide, unburned hydrocarbons and smoke well below existing regulations. Combustion section pressure loss and combustor outlet temperature distributions were substantially unchanged. The modified design was refined with the aid of computational fluid dynamics calculations to optimize the emissions reduction. Worthwhile reductions in NOx were obtained with combustor modifications that are transparent to the engine user.


1976 ◽  
Author(s):  
J. D. Holdeman

Emissions of total oxides of nitrogen, unburned hydrocarbons, carbon monoxide, and carbon dioxide from two J-58 afterburning turbojet engines at simulated high-altitude flight conditions are reported. Test conditions included flight speeds from Mach 2 to 3 at altitudes from 16 to 23 km. For each flight condition, exhaust measurements were made for four or five power levels from maximum power without afterburning through maximum afterburning. The data show that exhaust emissions vary with flight speed, altitude, power level, and radial position across the exhaust. Oxides of nitrogen (NOx) emissions decreased with increasing altitude and increased with increasing flight speed. NOx emission indices with afterburning were less than half the value without afterburning. Carbon monoxide and hydrocarbon emissions increased with increasing altitude and decreased with increasing flight speed. Emissions of these species were substantially higher with afterburning than without.


Author(s):  
Curtis M. Reeves ◽  
Arthur H. Lefebvre

Results of an analytical program to determine the effects of broad variations in fuel properties on the pollutant emissions generated by several prominent turbojet engine combustion systems, including both tubo-annular and annular configurations, are presented. Measurements of mean drop size conducted at representative engine operating conditions are used to supplement the available experimental data on the effects of combustor design parameters, combustor operating conditions, and fuel type, on pollutant emissions. The results of the study indicate that the fuel’s physical properties that govern atomization quality and evaporation rates have a significant effect on the emissions of carbon monoxide and unburned hydrocarbons. Analysis of the available experimental data shows that the influence of fuel chemistry on the emissions of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen, is small. Smoke emissions are found to be strongly dependent on combustion pressure, primary-zone fuel/air ratio, and the mode of fuel injection (pressure atomization or airblast). Fuel chemistry, as indicated by hydrogen content, is also important. Equations are presented for the correlation and/or prediction of exhaust emissions in terms of combustor size, combustor geometry, engine operating conditions, fuel spray characteristics, and fuel type.


1993 ◽  
Vol 115 (3) ◽  
pp. 570-580 ◽  
Author(s):  
G. J. Sturgess ◽  
R. G. McKinney ◽  
S. A. Morford

Measurements of the emissions from an experimental engine were analyzed to construct a design chart for the reduction of oxides of nitrogen (NOx) in conventional combustors. The design chart was used to reconfigure the stoichiometry distribution of the combustor of a production engine so as to reduce NOx while holding the emissions of carbon monoxide, unburned hydrocarbons, and smoke well below existing regulations. Combustion section pressure loss and combustor outlet temperature distributions were substantially unchanged. The modified design was refined with the aid of computational fluid dynamics calculations to optimize the emissions reduction. Worthwhile reductions in NOx were obtained with combustor modifications that are transparent to the engine user.


2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Soni S. Wirawan dkk

Biodiesel is a viable substitute for petroleum-based diesel fuel. Its advantages are improved lubricity, higher cetane number and cleaner emission. Biodiesel and its blends with petroleum-based diesel fuel can be used in diesel engines without any signifi cant modifi cations to the engines. Data from the numerous research reports and test programs showed that as the percent of biodiesel in blends increases, emission of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM) all decrease, but the amount of oxides of nitrogen (NOx) and fuel consumption is tend to increase. The most signifi cant hurdle for broader commercialization of biodiesel is its cost. In current fuel price policy in Indonesia (especially fuel for transportation), the higher percent of biodiesel in blend will increase the price of blends fuel. The objective of this study is to assess the optimum blends of biodiesel with petroleum-based diesel fuel from the technically and economically consideration. The study result recommends that 20% biodiesel blend with 80% petroleum-based diesel fuel (B20) is the optimum blend for unmodifi ed diesel engine uses.Keywords: biodiesel, emission, optimum, blend


Author(s):  
L. A. Diehl ◽  
J. A. Biaglow

Emissions and performance characteristics were determined for two full-annulus swirl-can modular combustors operated to near-stoichiometric fuel air ratios. The purposes of the tests were to obtain stoichiometric data at inlet-air temperatures up to 894 K and to determine the effect of module number by investigating 120 and 72 module swirl-can combustors. The maximum average exit temperature obtained with the 120-module swirl-can combustor was 2465 K with a combustion efficiency of 95 percent at an inlet-air temperature of 894 K. The 72-module swirl-can combustor reached a maximum average exit temperature of 2306 K with a combustion efficiency of 92 percent at an inlet-air temperature of 894 K. At a constant inlet air temperature, maximum oxides of nitrogen emission index values occurred at a fuel-air ratio of 0.037 for the 72-module design and 0.044 for the 120-module design. The combustor average exit temperature and combustion efficiency were calculated from emissions measurements. The measured emissions included carbon monoxide, unburned hydrocarbons, oxides of nitrogen, and smoke.


Author(s):  
R. J. Ketterer ◽  
N. R. Dibelius

This paper summarizes regulations from 80 countries covering air pollution emissions from gas turbines. The paper includes emission and ground level concentration standards for particulates, sulfur dioxide, oxides of nitrogen, visible emissions, and carbon monoxide.


Volume 2 ◽  
2004 ◽  
Author(s):  
Madhuri Jakkaraju ◽  
Vasudha Patri

I. C. Engines consume large amounts of fossil fuel emitting harmful pollutants like carbon monoxide (CO), unburnt hydrocarbons (UBHC), and oxides of nitrogen (NOx). By using a catalytic converter (CC), the carbon monoxide, hydrocarbon emissions can be transformed into less harmful carbon dioxide (CO2) & water vapor (H2O). Currently available CC’s are using costly noble metals like platinum (pt), palladium (pd), rhodium (rh) etc., hence making them expensive. This paper deals with the use of low-cost palletized silver coated alumina as the catalyst element in a CC. In this study, alumina and silver were used in the ratio of 10:1. All tests have been conducted on a stationary S.I. Engine at a constant speed of 1500 r.p.m with and without CC. Also, the performance of the palletized CC in combination with promoters like Bismuth, Cerium and Lanthanum was tested which have shown better results than silver alone as the coating element. It has been experimentally determined that the CO emissions have dropped from 7.25 (% vol) to 3.03(% vol) and the HC values have reduced from 350 ppm to 190 ppm.


2015 ◽  
Vol 72 (4) ◽  
Author(s):  
Arizal, M. A. A. ◽  
Jaafar, M. N. M.

A research has been done to observe the effect of varying the retainer angle on the performance of oil burner in terms of exhaust gas emissions and temperatures. Retainer was a flame stabilizer used to stabilize the flame, improve mixing between air and fuel and affect the formation of emissions such as carbon monoxide (CO), carbon dioxide (CO2), oxides of nitrogen (NOX), and sulfur dioxide (SO2). These emissions can cause harm to the world ecosystem. One of the methods to reduce emissions was by varying the retainer's blade angle to certain angle that complete the combustion with high efficiencies and less emissions. In this research, an oil burner with four different retainer angles has been investigated using a combustor of one meter length. Tests were conducted using diesel as feedstock. Four different retainer angles used are 15°, 30° (baseline), 45°, and 60° with swirl number 0.2016, 0.4344, 0.7524, and 1.3032. From the experiment, data shown that swirling flow affect the formation of recirculation zone thus provides the aerodynamics blockage to stabilize the flame and emissions reduced due to varying the retainer angles and the best retainer angle was achieved by consider the exhaust gas emission reduction.


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