Investigations into critical beat flux at low flow and pressure conditions are of particular interest when predicting the nuclear reactor core behavior during Loss of Coolant accident （LOCA）. Therefore, critical hea...Investigations into critical beat flux at low flow and pressure conditions are of particular interest when predicting the nuclear reactor core behavior during Loss of Coolant accident （LOCA）. Therefore, critical heat flux （CHF） has been investigated in a uniformly heated vertical round tube at two low system pressures and six low water flowrates. The results have been compared with two correlations which have different approaches and CHF look-up table. Good agreements have been obtained for the three comparisons at the lower sets of mass fluxes. The Bowring correlation was found to be the best to correlate the experimental results with Root Mean Square Error RMSE of 0.54% and 0.56% for the 5 bar and 15 bar system pressure respectively. A comparisons with the Shim and Lee correlation yielded RMSE of 0.23% and 5.74% for the two system pressure respectively. When the look-up table of Groeneveld et al. was used, RMES of 0.55% and 25.2% was obtained for the two system pressure respectively.展开更多
In this study, high-pressure hydrothermal processing of different biomass sources and products, which include cellulose, xylan, lignin, pine wood, paper waste, and waste lignin was performed at 200-275 ℃ in presence ...In this study, high-pressure hydrothermal processing of different biomass sources and products, which include cellulose, xylan, lignin, pine wood, paper waste, and waste lignin was performed at 200-275 ℃ in presence of NiSO4 catalyst. Biomass slurry was prepared in distilled water containing NiSO4, loaded in a high-temperature high-pressure reactor and heated to different temperatures. The reaction was continued for 120 min and during the reaction gas samples were withdrawn and analyzed using Chrompack capillary column on the gas chromatograph equipped with thermal conductivity detector. The analysis of gas samples revealed the presence of H2, CO2, CO, and CH4 gases. Increase in catalyst concentration from 3 wt% to 10 wt% has significantly increased the H2 generation. Absence of catalyst, however, generated almost negligible amount of H2. Among the biomass sources and products investigated here, xylan has yielded maximum amount of H2. The liquid samples were analyzed by high-performance liquid chromatography （HPLC） and Fourier transform infrared （FTIR） spectroscopy which revealed the presence of sugars along with the other intermediates.展开更多
文摘Investigations into critical beat flux at low flow and pressure conditions are of particular interest when predicting the nuclear reactor core behavior during Loss of Coolant accident （LOCA）. Therefore, critical heat flux （CHF） has been investigated in a uniformly heated vertical round tube at two low system pressures and six low water flowrates. The results have been compared with two correlations which have different approaches and CHF look-up table. Good agreements have been obtained for the three comparisons at the lower sets of mass fluxes. The Bowring correlation was found to be the best to correlate the experimental results with Root Mean Square Error RMSE of 0.54% and 0.56% for the 5 bar and 15 bar system pressure respectively. A comparisons with the Shim and Lee correlation yielded RMSE of 0.23% and 5.74% for the two system pressure respectively. When the look-up table of Groeneveld et al. was used, RMES of 0.55% and 25.2% was obtained for the two system pressure respectively.
文摘In this study, high-pressure hydrothermal processing of different biomass sources and products, which include cellulose, xylan, lignin, pine wood, paper waste, and waste lignin was performed at 200-275 ℃ in presence of NiSO4 catalyst. Biomass slurry was prepared in distilled water containing NiSO4, loaded in a high-temperature high-pressure reactor and heated to different temperatures. The reaction was continued for 120 min and during the reaction gas samples were withdrawn and analyzed using Chrompack capillary column on the gas chromatograph equipped with thermal conductivity detector. The analysis of gas samples revealed the presence of H2, CO2, CO, and CH4 gases. Increase in catalyst concentration from 3 wt% to 10 wt% has significantly increased the H2 generation. Absence of catalyst, however, generated almost negligible amount of H2. Among the biomass sources and products investigated here, xylan has yielded maximum amount of H2. The liquid samples were analyzed by high-performance liquid chromatography （HPLC） and Fourier transform infrared （FTIR） spectroscopy which revealed the presence of sugars along with the other intermediates.
