scholarly journals The estimations of the 10-11Pa range pressure measurement errors by a point collector gauge.

Shinku ◽  
1991 ◽  
Vol 34 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Fumio WATANABE
Author(s):  
J. Town ◽  
A. Akturk ◽  
C. Camcı

Five-hole probes, being a dependable and accurate aerodynamic tools, are excellent choices for measuring complex flow fields. However, total pressure gradients can induce measurement errors. The combined effect of the different flow conditions on the ports causes the measured total pressure to be prone to a greater error. This paper proposes a way to correct the total pressure measurement. The correction is based on the difference between the measured total pressure data of a Kiel probe and a sub-miniature prism-type five-hole probe. By comparing them in a ducted fan related flow field, a line of best fit was constructed. The line of best fit is dependent on the slope of the line in a total pressure versus span and difference in total pressure between the probes at the same location. A computer program, performs the comparison and creates the correction equation. The equation is subsequently applied to the five-hole probe total pressure measurement, and the other dependent values are adjusted. The validity of the correction is then tested by placing the Kiel probe and the five-hole probe in ducted fans with a variety of different tip clearances.


2019 ◽  
Vol 26 (2) ◽  
pp. 181-188
Author(s):  
Kazimierz Witkowski ◽  
Jacek Wysocki

Abstract The article discusses one of the most popular methods of diagnosing selected damages of marine piston engines, which is the indication or measurement of pressure changes in the engine’s combustion chamber. Improving the quality of indicator diagrams may contribute to the increase in the efficiency of using the parameters indicated in the diagnostics of marine piston engines. Measurement errors during engine indication are primarily caused by measuring channels that connect the combustion chamber to the pressure sensor. One way to avoid these errors is to install the pressure sensor directly in the combustion chamber. It seems that it is possible to eliminate these errors. However, there is a risk that the pressure sensor will be damaged by the effect of high temperature on it during combustion of the fuel-air mixture in the engine’s combustion chamber. The article presents the results of tests that indicate that the measured temperatures in the place where the sensor was installed (in the combustion chamber) did not exceed the critical value specified by the pressure sensor manufacturer. The article also presents the results of cylinder pressure measurement not only in the combustion chamber but also in two other points - on the thread of the indicator cock and in the measuring channel between the indicator cock and the cylinder head. The tests were carried out in a wide range of engine load technically efficient and with simulated damage in the fuel injection system. The article presents a comparative analysis of the parameters read out of the indicator diagram for the three above-mentioned pressure measurement locations. It was shown that the pressure measurements carried out directly in the combustion chamber are free from errors resulting from the influence of measuring channels and indicator cock.


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