CALCULATING SPECIFIC HEAT OF COMBUSTION PRODUCTS IN GAS MODE DIESEL ENGINES
The task of using natural gas-engine fuel in transport diesel engines (marine and automobile) is very actual. The trends of converting diesel engines to gas mode on ships of the port fleet and fishing vessels are becoming widespread. The importance to clarify the calculation methods of the working process for gas mode diesel engines is growing. Natural gas has been stated to comprise different gases - methane, ethane, propane, butane, carbon monoxide, etc., the percentage correlations of which being presented. There has been studied the method of calculating heat capacity of “pure” combustion products, i.e. under fuel combustion with excessive air coefficient α =1. The chemical reactions of oxidation elements of gas fuel components during its combustion determine the amount of kilomole of combustion products. To determine the heat capacity of the components of the combustion products - CO2, H2O and N2, the known tables of gases and water vapor properties were used. As a result of data processing, approximating linear and quadratic dependences were obtained. Нeat capacities are calculated in the linear formula of the specific heat of “pure” combustion products as the heat capacity of the gas mixture. As a result, a formula for determining the heat capacity of “clean” combustion products of gas fuel has been obtained: CVG = 25.03 + 0.0065· T . For determining the heat capacity of “clean” combustion products of gas fuel with 10% additive of ignition diesel fuel the formula has the following form CVGZH = 24.57 + 0.006· T . The dependences obtained are fairly accurate and recommended for using in the practice of converting diesel engines to gas-engine fuel, as well as when carrying out works and watercraft technology in building the ships and water transport.