Showing 3 results for Natural Gas
M. H. Askari, S. M. Hoseinalipour, S. A. Jazayeri, M. Baghsheikhi,
Volume 1, Issue 2 (6-2011)
Abstract
The HCCI combustion process is initiated due to auto-ignition of fuel/air mixture which is dominated by chemical kinetics and therefore fuel composition has a significant effect on engine operation and a detailed reaction mechanism is essential to analysis HCCI combustion. A single zone-model permits to have a detailed chemical kinetics modeling for practical fuels. In this study a single-zone thermodynamic model with detail chemical mechanism is developed to investigate the effect of hydrogen addition to natural gas in a homogeneous charge compression ignition combustion and to analyze the performance and emissions of the HCCI engine. The effect of five different percentage of hydrogen added to natural gas ranging from 0 to 40 on HCCI combustion is investigated in this study. The results indicate that by increasing hydrogen portion in intake mixture, start of combustion advances and maximum temperature increase, but increasing in maximum pressure is negligible. Carbon’s included emissions such as Co, Co2 and unburned hydrocarbons decreases by increasing of hydrogen, and also, specific fuel consumption decreases. The result shows that hydrogen improves combustion characteristics of natural gas in an HCCI engine and leads to better performance and less emissions.
A. Mirmohammadi, F. Ommi,
Volume 3, Issue 3 (9-2013)
Abstract
The purpose of present paper is simulation a direct injection stratified charge natural gas engine. The
KIVA-3V code was used for gaseous fuel injection simulation. Compression and expansion stroke of
engine cycle is simulated using KIVA-3V code. In cylinder fuel equivalence ratio distribution criterion is
used for studying mesh independency. The results show that 550000 cells number is sufficient. The
amount of NO emission in the end of closed cycle simulation was found equal 674.875 ppm and In cylinder
pressure versus engine crank angle degree was simulated that maximum value found in 366 oCA that equal
to 27.3222 bar.
Dr Ali Keshavarz, Fereshteh Khodamrezaee, Dr Sadegh Seddighi, Sepide Sarmast,
Volume 10, Issue 4 (12-2020)
Abstract
This work investigates the effects of hydrogen addition to compressed natural gas (CNG) on combustion characteristics and emission reduction using a closed cycle simulation with exact geometry of piston and cylinder head. The effect of equivalence ratio on combustion characteristic were investigated using a spark ignition (SI) engine fueled with CNG and addition of 10% vol, 15% vol and 20%vol hydrogen. Two different speed of 1500 and 3000 rpm have considered at full load condition. The modeling includes ECFM combustion model combined with K-ζ-f turbulent modeland has been done by AVL Fire software. Different volume fraction of Hydrogen with different excess air modeled and validated with experimental data. The validation procedure included in-cylinder pressure profile, maximum pressure, angle of maximum pressure, indicated mean effective pressure, and carbon monoxide (CO) emission showing a good agreement with the experimental results. The value of the peak pressure increases by hydrogen addition and it takes place sooner as the hydrogen volume fraction increases. However, the mean effective pressure drops 3.5%, 7% and 15% for HCNG 10, HCNG15 and HCNG20, respectively. CO emission decreases by increasing the hydrogen volume fraction. The results also indicate that hydrogen addition in lean combustion causes more CO reduction compared to the fuel-rich mixtures.
