NUMERICAL INVESTIGATIONS OF A DIESEL INTERNAL COMBUSTION ENGINE WHEN BURNING STEAM-GAS PRODUCTS OF WOOD PYROLYSIS AS THE BASIC FUEL

Abstract

The relevance of the research is caused by the need to conduct numerical studies of combustion in existing internal combustion engines with various injection designs and ignition systems for the fuel-air mixture of steam-gas pyrolysis products to generate mechanical energy on the crankshaft shaft. These directions will expand the role of pyrolysis of biomass, secondary products of wood processing enterprises and municipal solid waste in the field of heat and power complex. The main aim of this study is to evaluate the efficiency of combustion of gas-steam products of pyrolysis of wood waste in an internal combustion engine designed to use diesel fuel in order to be able to test this system. Objects: four-stroke diesel internal combustion engines of a V-shaped cylinder arrangement with and without a turbocharger, powered by the combustion of combined-cycle products of pyrolysis of wood waste. Methods: numerical studies based on mathematical algorithms of systems, cycles and main parts of naturally aspirated and turbocharged diesel internal combustion engines based on thermal calculations and thermal balance. Results. The authors have developed the mathematical model and a simulation program for thermal calculation of a four-stroke internal combustion engine with a V-shaped arrangement of cylinders with direct injection of combined-cycle products of wood pyrolysis into the combustion chamber with and without a turbocharging system. The analysis of the influence of the crankshaft speed, the number of cylinders on power, torque, and specific fuel consumption was carried out. It is shown that an increase in the number of cylinders with the same working volume of an internal combustion engine leads to growth in power and torque, while the specific consumption of steam-gas pyrolysis products decreases. It is noted that the combustion of steam-gas products of pyrolysis in an internal combustion engine leads to an increase in the temperature of the exhaust gases relative to diesel fuel combustion. For turbocharged internal combustion engines, the increase in exhaust gas temperature is about 50 °C, without turbocharging – about 100 °C. It was established that in the four-stroke diesel engine of internal combustion when burning pyrolysis gas obtained from wood waste, mass consumption is 7,5÷8,6 times more than diesel fuel is required to produce the same amount of electric energy. It was revealed that a diesel engine with a turbocharger is more economical and effective than a power unit without a supercharger. At a speed of 3000 min–1 of a 12 cylinder engine with a turbocharger, pyrolysis gas consumption saving is 11,9 %, effective capacity and torque are 10,0 % higher than that of an internal combustion engine without a supercharger. One of the most available at the moment for burning pyrolysis gas is a four-stroke V12 diesel engine with a turbocharged YAMZ 845.10 with a working volume of 25,86 liters, maximum capacity of 537 kW (730 hp), maximum torque of 2788 N⸱m at rotation frequency 1500÷3000 rpm.

Keywords

• internal combustion engine
• steam-gas pyrolysis products
• pyrolysis gas
• combustion chamber
• fuel-air mixture
• expansion ratio
• power
• working volume
• mathematical model