THE OXIDATION, IGNITION, AND DETONATION OF FUEL VAPORS AND GASES: XIV. THE CAUSE OF THE EFFECT OF HYDROGEN SULPHIDE TO REDUCE THE COMPRESSION RATIOS AT WHICH FUEL GASES CAN BE USED IN SPARK IGNITION ENGINES

1950 ◽  
Vol 28f (6) ◽  
pp. 166-176
Author(s):  
R. O. King ◽  
E. J. Durand ◽  
Bernard D. Wood ◽  
A. B. Allan
Keyword(s):  
Hydrogen Sulphide ◽  
Thermal Efficiency ◽  
Surface Reaction ◽  
Experimental Results ◽  
Spark Ignition Engines ◽  
Engine Operation ◽  
Poisoning Effect ◽  
Maximum Value ◽  
Full Power ◽  
Rich Mixtures

Experimental results are given for trials of the C.F.R. engine at 900 r.p.m. and 12: 1 C.R. on Toronto town gas alone and with an addition of hydrogen sulphide. The sulphide led to such severe preignition that measurements of power were impossible except for very weak or very rich mixtures. The former included the 50% weak mixture for which thermal efficiency is a maximum. The sulphide was then of beneficial effect, a maximum value of 44% for indicated thermal efficiency being obtained as compared to a maximum of 42.5% without it. The experimental results are interpreted in the light of combustion tube experiments showing that hydrogen in mixtures with air is not ignited by red hot surfaces on which it is oxidized with sufficient rapidity to steam, but that ignition occurs at relatively low temperatures if the surface reaction is inhibited by hydrogen sulphide. The conclusion is that fuel gases containing hydrogen in large proportion can be used for full power engine operation at compression ratios even higher than 12: 1 if the oxidation of the hydrogen in part to steam, on the hot surfaces in the combustion chamber, is not inhibited by the poisoning effect of the hydrogen sulphide commonly present in the gases.

Water-Ethanol-Gasoline Blends—Physical Properties, Power, and Pollution Characteristics

1984 ◽  
Vol 106 (4) ◽  
pp. 841-848 ◽  
Author(s):  
S. Rajan
Keyword(s):  
Physical Properties ◽  
Thermal Efficiency ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Oxides Of Nitrogen ◽  
Engine Operation ◽  
Nitrogen Emissions ◽  
Pollution Characteristics ◽  
The Road ◽  
On The Road

Factors relevant to the utilization of nonanhydrous ethanol as a blending component with gasoline for use in current on-the-road spark ignition engines are investigated. Miscibility limits are determined and key physical properties important for proper engine operation are measured. Dynamometer tests on an unmodified production engine with hydrated ethanol-gasoline blends containing varying percentages of water show potential for increased thermal efficiency and reduced oxides of nitrogen emissions.

Numerical Studies of Novel Aero Engine Secondary Combustors for Low-NOx Emissions

2020 ◽  
Author(s):  
Andrew Rolt ◽  
Victor Martínez Bueno ◽  
Mirko Romanelli ◽  
Xiaoxiao Sun ◽  
Pierre Gauthier ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Flow Region ◽  
Nox Emissions ◽  
Low Oxygen ◽  
Engine Operation ◽  
Horizon 2020 ◽  
Novel Technologies ◽  
Numerical Studies ◽  
Aero Engine

Abstract Gas turbine thermal efficiency and fuel burn are very dependent on turbine entry temperature and overall pressure ratio (OPR). Unfortunately, increases in these two parameters compromise other key aspects of engine operation and tend to increase emissions of nitrogen oxides (NOx). The European Horizon 2020 ULTIMATE project researched advanced-cycle aero engines with synergistic combinations of novel technologies to increase thermal efficiency without increasing emissions. One candidate technology was the addition of secondary combustion to increase the mean temperature of heat addition to improve thermal efficiency while limiting the primary combustor flame temperatures and NOx formation. However, an overall reduction in NOx also requires the secondary combustor to be a low-NOx design. This paper describes numerical studies carried out on novel aero engine secondary combustor concepts developed in two MSc-thesis research projects. The studies have explored the potential of oxy-poor-flame combustion concepts. These annular combustor designs featured two distinct regions: (i) the vortex zone, which promotes recirculation of combustion products, a prerequisite for low-oxygen combustion, and (ii) a through-flow region where part of the incoming flow bypasses the vortex before the flows mix again. These studies have demonstrated the advantages and some limitations of the proposed designs and emissions assessments in comparison with previous secondary combustor studies. They suggest very low NOx is achievable with oxy-poor combustion, but will be more difficult if the incoming oxygen levels are above 10%. More-accurate assessments will require LES modelling and inclusion of the primary combustor in the simulations. However, if the low overall NOx emissions would include relatively higher levels of nitrous oxide (N2O) then this might raise concerns with respect to global warming.

Principle and structure of a multi-chamber piezoelectric pump with large flow rate integrated into printed circuit board

2022 ◽  
pp. 1045389X2110721
Author(s):  
Yun-Hao Peng ◽  
Dai-Hua Wang ◽  
Lian-Kai Tang
Keyword(s):  
Flow Rate ◽  
Compression Ratio ◽  
Layer Structure ◽  
Experimental Results ◽  
Processing Technology ◽  
Rate Model ◽  
Piezoelectric Pump ◽  
Central Deflection ◽  
Maximum Value ◽  
Large Flow

Parametric simulation of multi-chamber piezoelectric pump proposed by authors shows that its flow rate is positively correlated with chamber compression ratio when height of chamber wall is not less than central deflection of circular piezoelectric unimorph actuator (CPUA). Therefore, in this paper, principle and structure of multi-chamber piezoelectric pump with novel CPUAs with three-layer structure are proposed and realized, so as to improve its chamber compression ratio, and then improve its flow rate. Its processing technology compatible with PCB processing technology is studied and its flow rate model is established. Central deflection of CPUA with three-layer structure and the flow rate characteristics are tested. Experimental results show that when the central deflection of CPUA with three-layer structure reaches the maximum value of 106.8 μm, the chamber compression ratio and flow rate of multi-chamber piezoelectric pump reach the maximum value of 50% and 3.11 mL/min, respectively. The maximum flow rate is increased by 622% compared to unimproved pump. By comparing experimental results with numerical and finite element simulation results, the realized multi-chamber piezoelectric pump has large flow rate and the established flow rate model can predict its flow rate.

scholarly journals A Stochastic Model for the Fractal Dimension Estimation of Asphaltenes Aggregation

2019 ◽  
Vol 8 (6) ◽  
pp. 1992-1995
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Stochastic Model ◽  
Production Systems ◽  
Experimental Results ◽  
Crude Oils ◽  
Dimension Estimation ◽  
Maximum Value ◽  
Solids Deposition

Some of the problems associated with the transportation of crude oils are due to the presence of heavy compounds as asphaltene molecules. This work developed a stochastic model that predicts the fractal dimension of the asphaltene aggregates. It was found that the maximum value of the fractal dimension is 1.71, which corresponds to the reported experimental results. The model can be applied as a universal growing behavior for the analysis of surface roughness when solids deposition is observed in the production systems involving crude oils

scholarly journals Effect of Bed Particle Size on Thermal Performance of a Directly-Irradiated Fluidized Bed Gas Heater

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 967
Author(s):  
Sae Han Park ◽  
Chae Eun Yeo ◽  
Min Ji Lee ◽  
Sung Won Kim
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Gas Velocity ◽  
Bubble Behavior ◽  
Heat Transfer Characteristics ◽  
Maximum Value ◽  
Solar Thermal Collector ◽  
Sic Particle

There is a growing interest in a fluidized bed particle receiver that directly irradiates sunlight to particles in the fluidized bed as a solar thermal collector for heating. Thermal performance of directly-irradiated fluidized bed gas heater is strongly affected by the physical properties of the particles. The effect of SiC particle size on heat transfer characteristics in the solar fluidized bed gas heater (50 mm-ID × 100 mm high) has been determined. The outlet gas temperatures showed a maximum value with increasing gas velocity due to the particles motion by bubble behavior in the bed, and the maximum values were found at 3.6 times of Umf for fine SiC and less than 2.0 times of Umf for coarse SiC. Heat absorption from the receiver increased with increasing gas velocity, showing with maximum 18 W for the fine SiC and 23 W for the coarse SiC at 4.5 times of Umf. The thermal efficiency of the receiver increased with increasing gas velocity, but was affected by the content of finer particles. The maximum thermal efficiency of the receiver was 14% for fine SiC and 20% for coarse SiC within the experimental range, but showing higher for the fine SiC at the same gas velocity. A design consideration was proposed to improve the thermal efficiency of the system.

ANALYSIS OF SURFACE ROUGHNESS AT OVERLAPPING LASER SHOCK PEENING

2016 ◽  
Vol 23 (03) ◽  
pp. 1650012 ◽  
Author(s):  
F. Z. DAI ◽  
Z. D. ZHANG ◽  
J. Z. ZHOU ◽  
J. Z. LU ◽  
Y. K. ZHANG
Keyword(s):  
Surface Roughness ◽  
Theoretical Analysis ◽  
Equilateral Triangle ◽  
Experimental Results ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Minimum Value ◽  
Maximum Value ◽  
Shock Peening ◽  
Iso 25178

The overlapping effects on surface roughness are studied when samples are treated by laser shock peening (LSP). Surface roughness of overlapped circular laser spot is calculated by ISO 25178 height parameters. The usually used overlapping styles namely isosceles-right-triangle-style (AAP) and equilateral-triangle-style (AAA) are carefully investigated when the overlapping degree in x-axis ([Formula: see text]) is below 50%. Surface roughness of isosceles-right-triangle-style attains its minimum value at [Formula: see text] of 29.3%, and attains its maximum value at [Formula: see text] of 43.6%. Surface roughness of equilateral-triangle-style attains its minimum value at [Formula: see text] of 42.3%, and attains its maximum value at [Formula: see text] of 32%. Experimental results are well consistent with theoretical analysis.

Performance Study of Flowing-Over PV/T System with Different Working Fluid

2014 ◽  
Vol 488-489 ◽  
pp. 1173-1176 ◽  
Author(s):  
Li Qing Tang ◽  
Qun Zhi Zhu
Keyword(s):  
Thermal Efficiency ◽  
Experimental System ◽  
Experimental Results ◽  
Working Fluid ◽  
Performance Study ◽  
Electrical Efficiency ◽  
Overall Efficiency ◽  
T System

This paper studied the performance of a flowing-over PV/T system with water and Al2O3 nanofluid as the working fluid. The experimental system was built in the outdoors. The parameters of the experiment obtained for processing, analysis, accessing to the electrical efficiency and thermal efficiency. Experimental results show that the flowing-over PV/T system with Al2O3 nanofluid as working fluid has a higher overall efficiency than that with water.

Influencing Factors of the HTR-10 Core Dynamics in Reactivity Insertion ATWS Tests

2016 ◽  
Author(s):  
Feng Gou ◽  
Fubing Chen ◽  
Yujie Dong
Keyword(s):  
Influencing Factors ◽  
Reactor Power ◽  
Sensitivity Analyses ◽  
Simulation Accuracy ◽  
Control Rod ◽  
Poisoning Effect ◽  
Core Dynamics ◽  
New Energy ◽  
Full Power ◽  
Reactivity Insertion

After the full power operation of the 10 MW High Temperature Gas-cooled Reactor-Test Module (HTR-10), several safety demonstration tests, representing the anticipated transient without scram (ATWS) conditions, were successfully performed on this reactor. Among these tests, two reactivity insertion ATWS tests were conducted by withdrawing a single control rod without reactor scram at 30% rated power. In the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University, these two tests have been reanalyzed using the THERMIX code, and the code itself was strictly checked through the test data. According to the previous code benchmark activities utilizing the HTR-10 tests, the temperature coefficient of reactivity (TCR), the residual heat level (RHL) and the xenon poisoning effect (XPE) could be considered the most important influencing factors of the THERMIX simulation accuracy for the core dynamics. In this study, sensitivity analyses are performed on the basis of the assumed variations of TCR, RHL and XPE. The impacts of these concerned parameters on the reactor power transient are qualitatively identified.

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