OPTIMAL PLATE ASPECT RATIO FOR THE BEST PERFORMANCE OF THE ENRICHMENT OF HEAVY WATER IN THERMAL-DIFFUSION COLUMNS OF A COUNTERCURRENT-FLOW FRAZIER SCHEME

The effect of plate aspect ratio on the performance of enrichment of heavy water in thermal-diffusion columns of a countercurrent-flow Frazier scheme was investigated. The equation for the optimal plate aspect ratios and the corresponding best performance were derived. Considerable improvement in performance is obtained when thermal-diffusion columns are operated at the optimal plate aspect ratio. Further improvement can be achieved if the scheme is connected and operated in countercurrent flow, instead of concurrent flow.     

THE OPTIMUM PLATE-SPACING FOR THE BEST PERFORMANCE IN FLAT-PLATE THERMAL DIFFUSION COLUMNS OF THE FRAZIER SCHEME

The effect of plate spacing on the degree of separation and production rate in flat-plate thermal diffusion columns of the Frazier scheme with fixed operating expense, has been investigated. The equations for estimating optimum plate-spacing for maximum separation and for maximum production rate have been developed. Considerable improvement in performance is obtainable when the thermal diffusion columns with optimum plate-spacing are employed for operation.     

THE PROPER COLUMN NUMBER FOR BEST PERFORMANCE IN THERMAL DIFFUSION COLUMNS OF THE FRAZIER SCHEME WITH TOTAL SUM OF COLUMN HEIGHT FIXED

The effect of column number on the Frazier scheme performances with total sum of column heights fixed has been investigated. The equations that may be employed to predict the optimal number of columns (generally not integers) for the maximum performance are derived. Accordingly, the proper number of columns, which are the integers nearest to and smaller than the optimal column numbers, are obtained for practical applications. Considerable improvement in performance is obtainable if the scheme is constructed with the proper number of thermal diffusion columns, instead of using a single column, with the same total sum of column heights.     

MASS TRANSFER IN LAMINAR FLOW IN CONCENTRIC-TUBE THERMAL-DIFFUSION COLUMNS FOR HEAVY WATER ENRICHMENT UNDER THE EFFECTS OF FLOW-RATE FRACTIONS AND RECYCLES

An orthogonal expansion technique for solving separation problems in laminar countercurrent concentric circular thermal-diffusion columns under flow-rate fraction variations is developed analytically and applied to heavy water enrichment. Experimental work for the H₂O–HDO–D₂O system has been also conducted. The present theoretical predictions are based on Sturmian theory, and positive and negative eigenvalues are needed for enriching and stripping sections, respectively, during the calculation procedure. The results show that the theoretical predictions are in better agreement with the experimental results than those predicted in previous works by using the transport equation.     

ENRICHMENT OF HEAVY WATER BY THERMAL DIFFUSION

Equations of the best wire angle of inclination for the maximum separation, maximum output and minimum column height for enrichment of heavy water in a concentric-tube wired thermal diffusion column have been derived. Considerable improvements in performance were obtained by employing the wired column instead of using the open column (without wire). It was also found that the wire inclination for maximum separation is also the wire inclination required to obtain the maximum production rate, or minimum column height, for a specified degree of separation.     

THE OPTIMUM PLATE-SPACING FOR THE BEST PERFORMANCE IN A FLAT-PLATE THERMAL DIFFUSION COLUMN WITH TRANSVERSE SAMPLING STREAMS

The equations for estimating optimum plate-spacing for maximum separation and for maximum production rate in a flat-plate thermal diffusion column with transverse sampling stream and with fixed operating expense, have been derived. Considerable improvement in performance is obtainable if the optimum plate-spacing is selected so that the convective strength can be properly reduced and controlled, resulting in suppressing the undesirable remixing effect while still preserving the desirable cascading effect and thereby leading to improved performance.     

软土地基中某埋地玻璃钢原水管爆管事故力学性能分析

近年来,南方某市供水管网埋地大口径玻璃钢原水管发生了6次较为严重的爆管事故,威胁了该管网的供水安全。为了研究管道出现事故的原因,对爆管处管道试样进行了力学性能试验,包括试样的拉伸、压缩、弯曲试验,同时根据管道所处地质条件,结合管道自身的力学性能参数对埋地玻璃钢管的受力性能进行理论计算和分析,包括管道长期变形、强度和管壁截面稳定。根据爆管处管道试验和理论计算结果推断管道爆裂的原因,同时提出相应建议以减少爆管事故的频繁发生。