International

As a tropical and highly mountainous country, Colombia has varying levels of atmospheric humidity across its regions. These humidity levels affect combustion parameters in premixed combustion systems such as laminar burning velocity, adiabatic flame temperature, and pollutant emissions. The greatest effect of water in the reaction zone is the reduction of NOx formation (at equilibrium) by up to 40% through the thermal mechanism for lean mixtures. The laminar burning velocity is reduced by up to 25% at an equivalence ratio of 0.5 and a molar moisture content of 3.5%.

In this paper, the part load operation of a dual fuel engine operating at 1500 m above sea level and its control using sonic flow meters for natural gas fuelling are presented. Dual fuel operation was established by retrofitting the intake system of a commercial Diesel engine with a port-injected gaseous fuels system, which was comprised by calibrated orifices working under sonic flow conditions. Natural gas mass flow rates throughout the orifices were estimated assuming the isentropic one-dimensional theory for perfect gases.

This research evaluated the operational conditions for a diesel engine with high compression ratio (CR) converted to spark ignition (SI), under stable combustion conditions close to the knocking threshold. The main fuel used in the engine was biogas, which was blended with natural gas, propane, and hydrogen.

This research evaluates the effect of the equivalence ratio on knocking tendency in two Spark Ignition (SI) engines fueled with gaseous fuels. A Lister Petter TR2 Diesel engine(TR2) converted to SI was used to evaluate the equivalence ratio effect when the engine was fueled with fuel blends of biogas, natural gas, propane, and hydrogen. A Cooperative Fuel Research (CFR) engine was used to study the effect of equivalence ratio on the Critical Compression Ratio (CCR) which is a metric to evaluate the knocking tendency of gaseous fuels.

This work presents the strategies applied to improve the performance of a spark ignition (SI) biogas engine. A diesel engine with a high compression ratio (CR) was converted to SI to be fueled with gaseous fuels. Biogas was used as the main fuel to increase knocking resistance of the blends. Biogas was blended with natural gas, propane, and hydrogen to improve fuel combustion properties. The spark timing (ST) was adjusted for optimum generating efficiencies close to the knocking threshold. The engine was operated on each blend at the maximum output power under stable combustion conditions.

The present study presents a numerical simulation of the effects of using self-recuperative burners on the performance of a walking-beam reheating furnace. The study was done using CFD (Computational Fluid Dynamics) simulations where a low computational cost method was implemented to simulate the billet heating as a steady state system. The preheating temperature of the air was defined as a function of the air mass flow and the flue gas temperature in each burner, using a UDF (User-Defined Function).

This research involves a knocking effect analysis of the operation and performance of a spark ignition engine with high compression ratio using a blend of 50% biogas with 50% natural gas. A diesel engine was converted to spark ignition mode. During testing, the output power, equivalence ratio, fuel blend composition and engine speed were kept constant while the spark timing was modified. Three knock intensities were evaluated using three different spark timing to evaluate the combustion parameters and engine performance. Eighteen tests were developed for repeatability analysis.

The increase of energy efficiency is an option to reduce greenhouse gas emissions (GHG). This benefits the industrial sector by reducing the energy consumption required to manufacture products, increasing production levels, and improving the competitiveness of the industry at a national and international level.

Surface-stabilized combustion (SSC) is a fuel-flexible technology that extends the stability limits of lean premixed systems, while achieving ultra-low emissions of NO_x, CO and UHC (unburned hydrocarbons). To evaluate these attributes, the present study quantifies (1) operability characteristics i.e., lean blowoff limit and flashback behavior and (2) pollutant emissions (CO, N₂O, NH₃, NO and NO₂) of a commercial SSC burner when operating at a fixed fire rate on a wide range of fuel compositions.

The polytropic coefficient is an important variable for determining errors in pressure and volume measurements and for apparent heat release calculation in engine combustion analysis. For commercial gasoline-fueled spark-ignition engines and diesel-fueled compression-ignition engines, a wide understanding about the thermodynamic models and values of the polytropic coefficient exists; however, in other technologies, in which gaseous fuels are used, the pressure treatment strategies and heat transfer models should be adjusted to allow for a better calculation of the polytropic coefficient.