Abstract
The various factors involved in determining the maximum flow of steam from a pressure vessel through straight pipes to the atmosphere are empirically correlated.
The main test series was conducted using four sizes of commercial pipe, 1·07, 0·84, 0·44 and 0·23 inches in diameter, and four sizes of stainless steel tube, 0·278, 0·17, 0·125 and 0·067 inches in diameter. The range of length/diameter ratios was 2·27 to 3000.
Two additional tests were conducted on 4-in pipe, using length/diameter ratios of 9 and 3000.
Flow rates were obtained by determining the relationships between flow and the critical† discharge pressures existing near the pipe outlet faces.
Results agree well with Lapple's theory for steel pipe of 1-in diameter and greater; for steel pipe less than 1-in diameter, flow rates are less than theory predicts.
For smooth tubes, flow rates are greater than Lapple's theory gives.
The effect on flow due to the position in a pipeline of a 90° square elbow, was also studied.
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