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Abstract The different fuel injection time, fuel injection pressure, fuel types were investigated to achieve low temperature premixed combustion in four-cylinder light-duty diesel engine using a common rail injection system. The two blending proportions of black soldier fly biodiesel (BD) at 10% and 20% BD-diesel blends were compared with pure diesel fuel in the present study. The combustion, performance, and emission of black soldier fly biodiesel were explored and compared with the conventional diesel combustion. Experimental outcomes showed that under low load, early and late injection time can attain low temperature premixed combustion that resulted in prolonged ignition delay and increased heat release rate. It has been observed that equivalent fuel consumption rate of black soldier fly biodiesel was driven higher (245–260 g/kWh) by increasing fuel injection time and fuel injection pressure but lower than pure diesel fuel (255–270 g/kWh). Moreover, an oxide of nitrogen emission rises with early fuel injection time (100–1200 ppm) compared to late fuel injection time (200–300 ppm), whereas the pure diesel fuel has lower emission 900 ppm at early fuel injection time but the rate was similar at late fuel injection time (200 ppm), whereas the early and late fuel injection time can reduce the smoke emission 0.02 l/m than diesel fuel which has smoke emission 0.04 l/m and 0.08 early and late fuel injection time respectively. The low blending ratio 10% BD recorded the reduction in the oxide of nitrogen emission (50%) than 20% BD and similar effects was observed for equivalent fuel consumption. The heat release rate was found to be high in higher fuel injection pressure due to the increase in the proportion of premixed combustion. Furthermore, the oxide of nitrogen emission was increased with the rise of fuel injection pressure, but smoke emission reduced during the process.

Abstract The different fuel injection time, fuel injection pressure, fuel types were investigated to achieve low temperature premixed combustion in four-cylinder light-duty diesel engine using a common rail injection system. The two blending proportions of black soldier fly biodiesel (BD) at 10% and 20% BD-diesel blends were compared with pure diesel fuel in the present study. The combustion, performance, and emission of black soldier fly biodiesel were explored and compared with the conventional diesel combustion. Experimental outcomes showed that under low load, early and late injection time can attain low temperature premixed combustion that resulted in prolonged ignition delay and increased heat release rate. It has been observed that equivalent fuel consumption rate of black soldier fly biodiesel was driven higher (245–260 g/kWh) by increasing fuel injection time and fuel injection pressure but lower than pure diesel fuel (255–270 g/kWh). Moreover, an oxide of nitrogen emission rises with early fuel injection time (100–1200 ppm) compared to late fuel injection time (200–300 ppm), whereas the pure diesel fuel has lower emission 900 ppm at early fuel injection time but the rate was similar at late fuel injection time (200 ppm), whereas the early and late fuel injection time can reduce the smoke emission 0.02 l/m than diesel fuel which has smoke emission 0.04 l/m and 0.08 early and late fuel injection time respectively. The low blending ratio 10% BD recorded the reduction in the oxide of nitrogen emission (50%) than 20% BD and similar effects was observed for equivalent fuel consumption. The heat release rate was found to be high in higher fuel injection pressure due to the increase in the proportion of premixed combustion. Furthermore, the oxide of nitrogen emission was increased with the rise of fuel injection pressure, but smoke emission reduced during the process.

Abstract Organic Rankine cycle (ORC) is a promising thermal-to-power technology that uses low-temperature heat from various sources including renewable energy and waste heat. A zeotropic fluid ORC offers thermodynamic-performance advantages over pure fluid ORC because of the relatively low irreversibility during the heat transfer process. Nonetheless, zeotropic fluid ORC may incur higher cost than pure fluid ORC because the former has high mass transfer resistance and small temperature difference in the heat exchanger. Limited research has been carried out to enhance thermo-economic performance of zeotropic ORC. In the present study, an ORC that uses zeotropic fluids and undergoes liquid–vapor separation during condensation is proposed. A thermo-economic analysis is developed based on a new optimization model for the proposed ORC. The objective function of the optimization model is the minimization of the specific investment cost. A genetic algorithm is used to solve the optimization model. A case study is then solved to illustrate the advantages of the proposed ORC and validate the proposed thermo-economic optimization method. The results of the thermodynamic analysis show that the condenser area of the proposed ORC is 17.6% lower than that of the conventional ORC under the same working conditions. Thermo-economic optimization results show that the specific investment cost of the proposed ORC is 13.3–18.4% lower than that of the basic ORC. Meanwhile, the second law efficiency of the proposed ORC is 4.2% higher than that of the conventional ORC. A sensitivity analysis is carried out to assess the dependence of the ORC performance on the temperatures of the heat source and the surrounding environment.

Abstract Organic Rankine cycle (ORC) is a promising thermal-to-power technology that uses low-temperature heat from various sources including renewable energy and waste heat. A zeotropic fluid ORC offers thermodynamic-performance advantages over pure fluid ORC because of the relatively low irreversibility during the heat transfer process. Nonetheless, zeotropic fluid ORC may incur higher cost than pure fluid ORC because the former has high mass transfer resistance and small temperature difference in the heat exchanger. Limited research has been carried out to enhance thermo-economic performance of zeotropic ORC. In the present study, an ORC that uses zeotropic fluids and undergoes liquid–vapor separation during condensation is proposed. A thermo-economic analysis is developed based on a new optimization model for the proposed ORC. The objective function of the optimization model is the minimization of the specific investment cost. A genetic algorithm is used to solve the optimization model. A case study is then solved to illustrate the advantages of the proposed ORC and validate the proposed thermo-economic optimization method. The results of the thermodynamic analysis show that the condenser area of the proposed ORC is 17.6% lower than that of the conventional ORC under the same working conditions. Thermo-economic optimization results show that the specific investment cost of the proposed ORC is 13.3–18.4% lower than that of the basic ORC. Meanwhile, the second law efficiency of the proposed ORC is 4.2% higher than that of the conventional ORC. A sensitivity analysis is carried out to assess the dependence of the ORC performance on the temperatures of the heat source and the surrounding environment.

Abstract A turbulent combustion test platform is designed. It is demonstrated that the turbulent environment in a constant volume combustion chamber is isotropic and controllable. Based on the platform, the turbulent combustion characteristics of methane/air are studied. The collected flame image and combustion pressure data are analysed. The results show that when the initial temperature is 300 K, the initial pressure is 1 bar, and the equivalence ratio is ϕ = 1 , the flame shape maintains self-similarity in the propagation process under different turbulence intensities. With the increase in turbulence intensity, there are more cracks on the flame surface and more wrinkles on the flame front; with the increase in turbulence intensity, the combustion propagation rate increases, the flame propagation rate increases at the same flame radius, and the maximum combustion pressure and the rate of pressure rise increase. When the turbulence intensity is constant, the test results of equivalence ratios of 0.8, 1.0 and 1.2 are compared. At an equivalent ratio of 1, the flame propagation rate and the stretch rate of the flame are maximized, and the maximum burning pressure and pressure rise rate are maximized.