Diesel–ethanol–waste cooking oil (WCO) blends are considered promising alternative fuels due to their renewability and potential for reduced emissions. This study investigates the spray and combustion characteristics of diesel and diesel–ethanol–WCO blends in a constant‐volume combustion chamber (CVCC). Blended fuels consisting of diesel, ethanol, and WCO with volumetric ratios of 90%–5%–5% (D90E5WCO5), 85%–10%–5% (D85E10WCO5), and 80%–15%–5% (D80E15WCO5), respectively, were tested. Prior to fuel injection, the chamber was maintained at chamber temperatures of 298 and 800 K under a constant pressure of 40 bar. Fuel injection was performed using a common‐rail system, and a high‐speed camera was employed to characterize spray tip penetration (STP), spray cone angle (SCA), and combustion behavior. The results indicate that at an ambient temperature of 298 K and an injection pressure of 200 bar, neat diesel exhibited the longest STP, whereas the D85E10WCO5 produced the largest SCA. Experiments conducted on the D80E15WCO5 under injection pressures ranging from 180 to 220 bar showed that both STP and SCA increased with increasing injection pressure. Under combustion conditions (800 K, 40 bar, and an injection pressure of 200 bar), neat diesel produced the highest peak pressure, whereas D85E10WCO5 exhibited the highest rate of pressure rise (ROPR) and rate of heat release (ROHR), indicating enhanced combustion performance. Overall, the results demonstrated that an appropriate combination of ethanol and WCO provides a favorable balance between spray atomization and combustion performance, highlighting the potential of diesel–ethanol–WCO blends as renewable alternative fuels for conventional compression‐ignition engines.
South Africa continues to rely on coal‐fired power plants for energy. The transition to renewable sources has begun, but this does not limit research on salvaging coal‐fired power plants. Considering the coal reserves in South Africa, before we fully give up on coal‐fired power plants due to their greenhouse gas emission concerns, research can continue to improve coal‐fired power plant performance. This study focused on developing a correlation that can be used to estimate the gross calorific value (GCV) of coal. The GCV of coal is an important metric in coal‐fired power plants (CFPP), since it shows the energy content of coal and can be used to analyze boiler performance and efficiency. Previous research has involved extensive work on developing correlations that can be used to estimate the GCV of coal using the ultimate and proximate analysis of coal, and it was found that these methods lead to delays in estimating the GCV of coal. This study investigated estimating the GCV of coal using live plant data, specifically the flue gas constituents, focusing on O 2 , C O 2 , N 2 and H 2 O . These flue constituents’ mass fractions have been confirmed to be measured at the CFPP. The methodology used included a mathematical simulation of coal combustion, which was validated using the literature; the model was then run using coal sample data from various coal grades and geographic regions. An adaptive network‐based fuzzy inference system (ANFIS) model was trained and validated to estimate the GCV of coal, and the model provided a coefficient of determination ( R 2 ) of 0.9107, RMSE of 1.661 MJ/kg, MAE of 1.189 MJ/kg, and a MAPE of 4.79%, which was favorable as compared to a multiple linear regression model. The ANFIS model showed strong predictive capability and adaptability, making it a promising tool for future energy and combustion‐related applications.
Natural gas is a clean, environmentally friendly, new, and efficient energy source. Due to its lower pollutant emissions, it is gradually being adopted to replace traditional fossil energy in the architectural ceramics industry. For industrial production, the air disc at the outlet of the swirl burner is crucial for ensuring the burner’s adequate combustion. In the present study, the structure of the existing swirl burner used in the architectural ceramics industry was improved and optimized, and a three‐dimensional CFD numerical simulation was conducted. The results show that as the blade angle increases, combustion stability is enhanced, with a slight increase in flame length. Meanwhile, when the blade angle is 25°, the emissions of CO and NO gradually decrease, and combustion efficiency is improved. As the swirler thickness increases, the high‐temperature zones expand, and CO and NO emissions are reduced. Specifically, when the swirler thickness is 14 mm, CO and NO emissions are significantly decreased; compared with those at 8 mm, NO emissions are reduced by 72.73%. This work provides a reference for the application of hydrogen‐blended natural gas in swirl burners.
Natural gas is a clean, environmentally friendly, new, and efficient energy source. Due to its lower pollutant emissions, it is gradually being adopted to replace traditional fossil energy in the architectural ceramics industry. For industrial production, the air disc at the outlet of the swirl burner is crucial for ensuring the burner's adequate combustion. In the present study, the structure of the existing swirl burner used in the architectural ceramics industry was improved and optimized, and a three-dimensional CFD numerical simulation was conducted. The results show that as the blade angle increases, combustion stability is enhanced, with a slight increase in flame length. Meanwhile, when the blade angle is 25 degrees, the emissions of CO and NO gradually decrease, and combustion efficiency is improved. As the swirler thickness increases, the high-temperature zones expand, and CO and NO emissions are reduced. Specifically, when the swirler thickness is 14 mm, CO and NO emissions are significantly decreased; compared with those at 8 mm, NO emissions are reduced by 72.73%. This work provides a reference for the application of hydrogen-blended natural gas in swirl burners.
This paper presents a comparative study between natural and mechanical smoke extraction during fire in a high-rise building. Experiments were conducted in a small scale F + 1 building with dimensions 1.23 x 1.23 x 2.0 m. A stair-well of dimensions 0.22 x 0.22 m allowed the passage between the first floor and the second floor. This experimental device was operated under two configurations. Configuration 1 which studied the natural extraction of smoke through the window of Floor 1, and Configuration 2 which focused on the mechanical evacuation of smoke owing to an extractor located on the main side at 1.95 m above the floor. Fire tests were performed in both configurations with a constant fire source. Results reveal that the temperature variation over time shows a maximum smoke temperature of 145 degrees C in Configuration 1 compared to 85 degrees C in Configuration 2. Furthermore, at time t = 400 s, temperature reaches 90 degrees C in Configuration 1 compared to 64 degrees C in Configuration 2. All these results highlight the role of mechanical extraction in improving the evacuation of smoke and hot gases. This process facilitates both occupant evacuation and emergency response as part of a fire safety strategy.
