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Volume 28, Issue 98
Displaying 1-5 of 5 articles from this issue
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C. WIESELSBERGERArticle type: Article
1925 Volume 28 Issue 98 Pages 357-364
Published: 1925
Released on J-STAGE: August 01, 2017
MAGAZINE FREE ACCESSThe most important aerodynamical qualities that should be aimed at in wind-tunnel design are as follows : (1) Constant and parallel direction of flow (2) Uniform velocity across all sections (3) Absence of turbulent motion (4) Constant velocity of flow. The Gottingen type of wind-tunnel with a parallel part before the working section, whose section is steadily reduced, realises in a high degree all above mentioned qualities. It is shown, that this system can easily applied for other wind tunnels for inst. N.P.L. or Eiffel type. An ultimatly constructed Eiffel tunnel of 1.25m diameter, whose design was based on this principle, gave very satisfactory results.View full abstractDownload PDF (502K) -
[in Japanese]Article type: Article
1925 Volume 28 Issue 98 Pages 365-370
Published: 1925
Released on J-STAGE: August 01, 2017
MAGAZINE FREE ACCESSThe condition of steam supply for the locomotive in motion greatly differs from that of the general case, in which ordinary steam engines are employed as generative machines. During the running of locomotive, steam force is applied for 60 to 70 per cent. of the time in operation, while for the remaining 30 to 40 per cent. practically no steam is used, the motion being merely continued by inertia of the running train and availing of gradients of lines, in other words ; the steam supplying condition being usually intermittent, will make, as a rule, the charge of boiler variable according to the time of re-feeding of boiler water. With system of feed-water heating arrangements in locomotive in general use, the feed of hot-water is only possible while the locomotive is running with throttle opened and thereby the boiler is forced very heavy which consequence being to lewor its efficiency, and thus the gain from the hot feed is canceled to some extent, by reducing the boiler efficiency. Now, according to my system, it is possible to feed hot water during the whole course of running either with or without throttle opened by providing with the auxiliary hot water tanks, and thus we can get the combined advantageous effects of the hot feed and improving the boiler efficiency at the same time.View full abstractDownload PDF (625K) -
[in Japanese]Article type: Article
1925 Volume 28 Issue 98 Pages 371-385
Published: 1925
Released on J-STAGE: August 01, 2017
MAGAZINE FREE ACCESSThe heat carried off by fluid from a surface, apart from the effect of radiation, is proportional to the internal diffusion of the fluid at and near the surface. The rate of this diffusion depends first on the nature of the fluid and secondly on the effect of eddies which arises entirely from the motion of the fluid and is proportional both to the density of the fluid and the velocity with which it flows past the surface. Using the apparatns shown in the figure, we investigated the heat transmission between water through the condenser tube wall and verified Reynolds' law of heat transmission. It was also shown that the twisted retarder inserted in the cooling water passage substantially improved the transmission of heat. Moreover a phenomena which was supposed to be the effect of the critical velocity was observed in the experiment.View full abstractDownload PDF (1025K) -
[in Japanese]Article type: Article
1925 Volume 28 Issue 98 Pages 386-396
Published: 1925
Released on J-STAGE: August 01, 2017
MAGAZINE FREE ACCESSIn forging shops, the ingot or bloom is sometimes forged either by first stamping sideways and then upsetting or by these procedures in reverse order. The object of this investigation is to find out some effects caused by the above mentioned processes upon the properties of the material, comparing with the known fact that the ordinal forging brings good effects to longitudinal test but injurious to transverse. In the present experiment, the material was subjected to the lengthening and upsetting operations and we found that the result of the material tests indicated the existence of the combined effect of the good and bad influences of the each operation. We found also that the last forging was more effective than the foregoing and therefore chiefly determined the final mechanical properties of the matorial.View full abstractDownload PDF (884K) -
[in Japanese]Article type: Article
1925 Volume 28 Issue 98 Pages 397-428
Published: 1925
Released on J-STAGE: August 01, 2017
MAGAZINE FREE ACCESSThe efficiency of the centrifugal pump depends very largely on the efficiency of converting the kinetic energy of the water leaving the impeller into the pressure form. There are the two methods of enorgy-conversion generally adopted by designers of centrifugal pumps : one is to use the vortex or whirlpool chamber and the other the guide vane. And modern pump design appears to be tending to use the vortex chamber for low and medium types and the guide vane for high pressure type. The object of the experiments is to study if any variation in the efficiency and other characteristics of a high pressure centrifugal pump occurs, when fitted with guide vanes of different vane angle at entrance and divergent vortex chamber without guide vanes. This is the results obtained in each case. The comparison between the guide vanes and vortex. chamber is perhaps best seen from the attached figures. It would be generally stated that even for a high pressure centrifugal pump the good efficiency is obtainable from vortex chamber pump as from guide vane pump provided that a correct design of the vortex chamber is made, and also, that since the efficiency of the pump fitted with guide vane depends largely on the suitability of the vane angles, great care should be taken in the determination of the vane angle.View full abstractDownload PDF (2299K)
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