A shell-and-tube heat exchanger with separated baffles parallel to segmental baffles was proposed, and an investigation on velocity distribution, heat transfer and flow resistance characteristics in the shell side of ...A shell-and-tube heat exchanger with separated baffles parallel to segmental baffles was proposed, and an investigation on velocity distribution, heat transfer and flow resistance characteristics in the shell side of the proposed heat exchanger and traditional single segmental baffled shell-and-tube heat exchanger was reported. After the experiment, the empirical relations of heat transfer and flow resistance were obtained. The heat transfer enhancement comprehensive evaluation factor η was in the range from 1.15 to 1.20 for Reynolds number (1.25×10 4—3.35×10 4). The results indicated that flow field uniformization was enhanced in the shell side of shell-and-tube heat exchangers by two separated baffles parallel to segmental baffles and the performance of heat transfer was improved by controlling the dimension of vortices. The results could be used as reference in further research.展开更多
A rapid and sensitive spectrophotometric method was proposed for the detemination of I-with sequential injection stopped-flow technique,based on the effect of I-on the reaction between iron thiocyanate and NO2-.The ex...A rapid and sensitive spectrophotometric method was proposed for the detemination of I-with sequential injection stopped-flow technique,based on the effect of I-on the reaction between iron thiocyanate and NO2-.The experimental parameters were optimized by single factor method.The linear range for determination of I-was 0.4 mg·dm-3～4.0 mg·dm-3,and the detection limit was 0.3776 mg·dm-3.The relative standard deviation was 1.2% via nine repeated determination of 2 mg·dm-3 I-.The method was applied to determine the quality of I-in food water samples with satisfactory results.展开更多
文摘A shell-and-tube heat exchanger with separated baffles parallel to segmental baffles was proposed, and an investigation on velocity distribution, heat transfer and flow resistance characteristics in the shell side of the proposed heat exchanger and traditional single segmental baffled shell-and-tube heat exchanger was reported. After the experiment, the empirical relations of heat transfer and flow resistance were obtained. The heat transfer enhancement comprehensive evaluation factor η was in the range from 1.15 to 1.20 for Reynolds number (1.25×10 4—3.35×10 4). The results indicated that flow field uniformization was enhanced in the shell side of shell-and-tube heat exchangers by two separated baffles parallel to segmental baffles and the performance of heat transfer was improved by controlling the dimension of vortices. The results could be used as reference in further research.
文摘A rapid and sensitive spectrophotometric method was proposed for the detemination of I-with sequential injection stopped-flow technique,based on the effect of I-on the reaction between iron thiocyanate and NO2-.The experimental parameters were optimized by single factor method.The linear range for determination of I-was 0.4 mg·dm-3～4.0 mg·dm-3,and the detection limit was 0.3776 mg·dm-3.The relative standard deviation was 1.2% via nine repeated determination of 2 mg·dm-3 I-.The method was applied to determine the quality of I-in food water samples with satisfactory results.
基金The National Natural Science Foundation of China (No.50976022)the National Key Technology R&D Program of China during the 11th Five-Year Plan Period (No.2008BAJ12B02)
