模型單螺旋船後に於ける四翼推進器の試験
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概要
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In the previous paper, the Authors dealt with the open water tests on 4-bladed propellers of three series, namely, increasing pitch, constant pitch and decreasing pitch. The general plan of the propellers and the test results are represented in Fig. I and Fig. 2 respectively. The present paper is an account of experiments, successively carried out at the Teisinsyo Ship Experiment Tank, with the same series of propellers working behind a rather fine single-screw cargo ship model fitted with an ordinary stream-lined rudder. The ship model, the characteristics of which are shown in Fig. 3. was towed at a speed of about 2-0 m/s throughout the tests, so as to keep the condition of flow constant ; while the propellers were driven over possibly wide range of slip. The radial wake distribution measured by blade wheels is given in Fig. 5. The test results presented in Fig. 6 were analysed depending upon the equivalent advance speed derived from the method of torque-constant identity. Fig. 8 gives the relative rotative efficiency for the usual range of slip plotted on the base of real slip. Generally independent of the pitch ratio, the relative rotative effciency decreased more and more slowly, as the slip increased. Accordingly, within the range of working slip, the relative rotative efficiency can be reckoned as constant for a narrow range of slip. It may therefore be suggested that the diameter giving the best propeller efficiency behind a ship of such type as represented by the model used is almost the same as, or a little greater than that in open water. So far as the present experiments concerned, the increasing pitch propellers gave higher relative rotative efficiency than the constant pitch propellers did, and the decreasing pitch propellers the lower. But, those differences, especially at higher slip, were not remarkable.
- 社団法人日本船舶海洋工学会の論文
- 1941-09-30