REGRESSION EQUATIONS FOR CALCULATING THE SOLUBILITY OF HYDROGEN IN LIQUID FUELS

The efficiency of combustion of liquid fuels in heat engines is determined by their hydrocarbon composition. The rate of combustion and the completeness of combustion depend on the hydrocarbon composition of the fuel. One of the ways to increase the efficiency of combustion of fuel is to use fuel-hydrogen mixtures. The use of such mixtures gives prerequisites for low-temperature self-ignition of fuel droplets (about 590 °C). Preheating of the fuel gives the possibility of "explosive" combustion with increasing of the temperature up to 2500 K in 0.02 –. 0.04 ms. This leads to the intensification of heavy fuel combustion. The use of fuel-hydrogen mixtures allows to obtain a low level of harmful emissions with flue gases and to reduce emissions: CO and CH – not less than 15%, CO2 – not less than 20%. A promising direction for the creation of such mixtures is the direct dissolution of hydrogen in liquid fuel. This simplifies the flow of the fuel-hydrogen mixture into the combustion chamber of the heat engine or into the cylinders of the internal combustion engines. Analysis of previous studies showed the possibility of obtaining a single form of regression dependence for calculations of the dissolution of hydrogen in liquid fuels. The processing of the literature data and the results of our own research gave a set of regression equations for calculating the solubility of hydrogen in liquid fuels: gas, diesel, fuel oil, LVGO, HVGO, GDAR, ABVB. The obtained regression dependencies show that with increasing average molecular weight the solubility of hydrogen in the fuel decreases. These regression dependencies make it possible to obtain baseline data for the design of fuel systems for supplying fuel and hydrogen mixtures to combustion chambers of heat engines. Studies of hydrogen-diesel have shown a decrease in the flash fuel temperature by 10 – 15 oC by comparison with pure fuel. For heavy fuels, this level of reduction of the fuel round is not sufficient. Therefore, it is necessary to conduct further studies on the intensification of the process of dissolution of hydrogen in heavy fuels. This will significantly reduce energy costs for the organization of the combustion process.

Advanced Catalytic Igniters Technology for Small Compact Engine Applications

Development of technologies that allow small, high power density engines such as unmanned aerial vehicles (UAV), unmanned marine vehicles (UMV), and unmanned ground vehicles (UGV) to operate on single logistic fuel such as JP-8 is one of government goals. To advance this goal, a lightweight, compact, and retrofit capable ignition source is critical. Compared to standard spark igniters and noncatalytic glow plugs, the use of catalytic glow plugs will provide benefits of lower required compression ratio, improved igniter life, reduced electrical energy requirements, and overall reduction in system weight and size. Experimental testing demonstrated a significant increase in surface temperature (160+ °C) with impingement of a fuel spray compared to a conventional glow plug with engine testing demonstrating the use of catalyst allows stable engine operation at reduced power requirements. Computational analysis was performed to provide insight into the catalyst behavior. Analytical studies suggested increased stability due to both heat release due to exothermic catalytic reaction and production of reactive species. This technology would allow high power density engines to use heavy fuels, while potentially reducing electric power supply and engine complexity and weight, both of which would allow greater range and/or payload capacity. This paper discusses the feasibility of advanced igniters technology as an enabling component for the use of heavy fuels in small, high power density internal combustion engines. The paper presents and discusses analytical investigation, experimental test results, and durability testing data in an internal combustion engine environment.

Advanced Technology Igniter for High Power Density Engines

With current DoD goals of switching to a common logistics fuel, there is a significant drive to develop technologies that allow small, high power density engines such as used in unmanned aerial, marine, and ground vehicles, typically fueled by volatile fuels such as gasoline, to operate on heavy fuels such as JP-8. In this paper, the potential of advanced catalytic glow plugs as an enabling component for the use of heavy fuels both as a retrofit to existing engines as well as new engine designs is demonstrated. Compared to standard spark igniters and non-catalytic glow plugs, the use of catalytic glow plugs will provide benefits of lower required compression ratio, improved igniter life, reduced electrical energy requirements, and overall reduction in system weight and size. The advanced catalytic glow plug was demonstrated to have a significant increase in surface temperature (180+ °C) with impingement of a fuel spray. Engine testing demonstrated that the use of catalyst allowed stable engine operation at reduced power requirements. This technology would allow high power density engines to use heavy fuels, while potentially reducing electric power supply and engine complexity and weight, both of which would allow greater range and/or payload capacity.