Numerical analysis of the performance and NOx emission of a diesel engine fueled with algae biofuel-diesel blends

Researchers are looking for alternative energy sources, and biofuel from algae has a significant contribution as an alternative renewable fuel. This paper aims to evaluate fundamental running parameters (heat release rate, peak pressure, specific fuel consumption, and brake torque) and estimates the factors influencing nitrogen oxides (NOx) formation for algae biofuel-diesel blends (A-diesel). The analyses were done using a thermodynamic model and simulated with Diesel-RK and ANSYS. The numerical results of Diesel-RK and ANSYS were validated with experimental in-cylinder pressure data, and also compared with existing literature where needed. Injection timing, engine speed, and inlet temperature were selected as variables for developing the model. The engine speeds were chosen from 1400 rpm to 2500 rpm, and the injection timings were varied from 30 degrees Before Top Dead Center (BTDC) to 20 degrees After Top Dead Center (ATDC). Three algae biofuel blends such as 5% Algae-oil and 95% diesel (A5), 10% Algae-oil, and 90% diesel (A10), 15% Algae-oil and 85% diesel (A15), and pure diesel were considered as fuels for the analysis. The numerical findings indicate that higher inlet temperature, in-cylinder combustion temperature, and advanced injection timing are the main reasons for higher NOx formation during combustion. Among all the four fuels, algae bio-fuel blends showed lower NOx formations than conventional diesel fuel, and also, the engine performance was satisfactory. These two developed numerical models will also help researchers investigate various fundamental parameters of a diesel engine using blended fuels.