Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the start...Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope(SEM), Energy Dispersive Spectroscopy(EDS) and Fourier Transform Infrared Spectroscopy(FTIR) methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, Cu Co-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of Cu Co-I nano-catalyst.展开更多
Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cow...Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cowl shape on the ramp surface pressure distribution is discussed and compared with existing V-Notch [90°] intake model at free exit condition. It was found that using pointed cowl [90°] intake model, a better pressure recovery was achieved compared to the V-Notch [90°] intake model at Mach 2.2. Both Pointed and V-Notch intake models showed good starting characteristics. For change in back pressure, the occurence of normal shock, flow separation zone and flow reversal were observed. All experiments are performed only for the Pointed cowl [90°] intake model. All the 3-D computations were performed by using software available at B.I.T, Mesra, Ranchi.展开更多
文摘Nano-catalysts containing copper–cobalt oxides(Cu–Co–O) have been synthesized by the citric acid(CA) complexing method. Copper(II) nitrate and Cobalt(II) nitrate were employed in different molar ratios as the starting reactants to prepare three types of nano-catalysts. Well crystalline nano-catalysts were produced after a period of 3 hours by the calcination of CA–Cu–Co–O precursors at 550 °C. The phase morphologies and crystal composition of synthesized nano-catalysts were examined using Scanning Electron Microscope(SEM), Energy Dispersive Spectroscopy(EDS) and Fourier Transform Infrared Spectroscopy(FTIR) methods. The particle size of nano-catalysts was observed in the range of 90 nm–200 nm. The prepared nano-catalysts were used to formulate propellant samples of various compositions which showed high reactivity toward the combustion of HTPB/AP-based composite solid propellants. The catalytic effects on the decomposition of propellant samples were found to be significant at higher temperatures. The combustion characteristics of composite solid propellants were significantly improved by the incorporation of nano-catalysts. Out of the three catalysts studied in the present work, Cu Co-I was found to be the better catalyst in regard to thermal decomposition and burning nature of composite solid propellants. The improved performance of composite solid propellant can be attributed to the high crystallinity, low agglomeration and lowering the decomposition temperature of oxidizer by the addition of Cu Co-I nano-catalyst.
文摘Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cowl shape on the ramp surface pressure distribution is discussed and compared with existing V-Notch [90°] intake model at free exit condition. It was found that using pointed cowl [90°] intake model, a better pressure recovery was achieved compared to the V-Notch [90°] intake model at Mach 2.2. Both Pointed and V-Notch intake models showed good starting characteristics. For change in back pressure, the occurence of normal shock, flow separation zone and flow reversal were observed. All experiments are performed only for the Pointed cowl [90°] intake model. All the 3-D computations were performed by using software available at B.I.T, Mesra, Ranchi.
