摘要:

An equation for calculating the pressure drop in gas flow accompanied by large temperature change, derived from the differential form of the Bernoulli theorem combined with the heat transfer rate equation, was examined experimentally. Heating runs were made in the Reynolds number range 6000 to 15,000, for air flowing through a single horizontal. standard steel pipe with steam jacket. The pressure drops calculated from the proposed equation were found to agree very closely with the observed experimental values. The method of evaluating pressure drop for turbulent nonisothermal flow by assuming isothermal conditions at a temperature midway between the surface temperature and the mean bulk temperature of the fluid, first developed by McAdams for certain oils, was also tested for a number of selected runs. This method was found to be as accurate as the previous one, and to have the advantage of being less cumbersome in application.

ISSN:1923-4287    

DOI:10.1139/cjr48f-049

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Western Electric bead type thermistors were used to determine the difference in temperature of the water between the headrace and tailrace of a hydraulic turbine at different loads on the turbine. From this temperature difference the maximum efficiency of the turbine was determined to be 92% and the unit flow of water in cubic feet per second was calculated.

ISSN:1923-4287    

DOI:10.1139/cjr48f-050

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Tests concluded with an airborne magnetic detector measuring the earth's total field indicate a high degree of accuracy and speed for reconnaissance work over large areas. Cheapness of operation and freedom from small local anomalies make this a valuable tool for geophysical prospecting.

ISSN:1923-4287    

DOI:10.1139/cjr48f-051

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The nature of the intensifying action of lead screens and Patterson screens has been investigated for gamma radiography. For the lead screens used it was found that nearly 52% of the blackening of the film is due to electrons ejected from the front screen and nearly 48% due to electrons ejected from the back screen. The blackening of the film due to the absorption by the film itself of the radiation is small. Similar results were obtained with Patterson screens except that about 10% of the effect of the screens is due to low energy radiation (light) which was stopped by 3 mgm. per cm.2of aluminum.

ISSN:1923-4287    

DOI:10.1139/cjr48f-052

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

This paper contains but a single idea. Its purpose is to show how, by the use of Kleinlogel's Rahmenformeln, the number of simultaneous linear equations that occur in the analysis of indeterminate structures can be reduced materially by using a primary structure, itself made up of indeterminate parts, provided the bending moment diagrams can be drawn for them. These are obtained from the Rahmenformeln. In order to recall to the reader's mind the well known moment-area method a brief summary of that process is included. A practical numerical example of the analysis of a frame indeterminate to the seventh degree is worked out in detail. Two arrangements of the indeterminate-components are chosen in the illustrative example. The final bending moment diagram is shown for a simple loading case and the influence line for the bending moment at one point is discussed briefly.

ISSN:1923-4287    

DOI:10.1139/cjr48f-053

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A method has been developed for calculating the temperature variation in insulated thermocouple lead wires that do not follow an isothermal path. The difference between the temperature of the junction and that of the surrounding material that it purports to measure has been called "insulation error." It has been shown that insulation error is determined by variations in the temperature of the path followed by the lead wires only over a limited distance from the junction, which has been called the "critical distance." Hence, to eliminate insulation error the path of the wires need be isothermal only for the critical distance. A simple method has been developed for calculating the critical distance and the insulation error. When the path of the wires cannot be made isothermal the conditions for minimum experimental error are shown to be small diameter wires of low specific conductivity with a minimum of insulation.

ISSN:1923-4287    

DOI:10.1139/cjr48f-054

出版商:NRC Research Press    

年代:1948

数据来源: NRC