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ASME PTC 19.1 TEST UNCERTAINTY PDF

The edition of ASME PTC will be revised when the Society approves the issuance of the next edition. There will be no Addenda issued to ASME PTC. ASME PTC Test Uncertainty [ASME] on *FREE* shipping on qualifying offers. The scope of this Code is to specify procedures for . (Revision of ASME PTC ). Test Uncertainty. Performance Test Codes. AN AMERICAN NATIONAL STANDARD. Two Park Avenue • New York, NY.

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ASME PTC – Test Uncertainty

Usually, test conditions vary between these two extremes and it is not possible to correct the readings in a simple manner. An w example may be an air conditioner that was bench tested in a kncertainty but used in an automotive mechanics shop. Special tests had previously been conducted to determine if taking additional traverse points 20 along each of the 4 radii would result in a significant change in the measurement of the overall average velocity in the pipe, as computed using eq.

The term sc in eq. Program 2 correlated systematic uncertainties: A weighting principle which is statistically valid 4. When a uncertaity is calculated from the sample, the degrees of freedom associated with the statistic is reduced by one for w every estimated parameter used in calculating the statistic.

A forward differencing scheme wsme used with a value of Qx equal w to 0.

ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心

Specifically, a tolerance interval is applicable if o limits are needed that contain most of the sampled population, while a prediction interval would be used to obtain limits to contain all of a small. The fx sample standard deviation SX and the mean X of the sample are calculated. The thermocouples from each multiprobe array were connected in parallel in a manner w which yielded a spatially averaged temperature measurement. The difference between the results of these tests is an indication of the effect of the design change.

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Additionally, a pretest uncertainty analysis facilitates communication between all parties to the test about the expected quality of the test. Measurements of the total pressure and total temperature at the inlet and exit of the compressor were collected at one minute intervals resulting in 60 discrete measurements of each parameter over the test period. Thus, it often is necessary to install several measurement sensors at different spatial locations to account for spatial variations of the parameter being measured.

ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf

Two tests are in common usage for determining whether or not spurious data are outliers. Some are also aware of tolerance intervals, but most nonstatisticians know very little uncfrtainty prediction intervals despite their tewt importance. The test conclusion that can be drawn from this figure is the pump is operating consistently when compared since the uncertainty bands overlap.

The second number specifies the probability that the calculated interval really contains at least the specified proportion of the population.

The population mean is therefore of great interest in characterizing product performance, and is often used as a standard by which competing processes are compared. The significance of this is discussed in para.

Inspection of Table The steps in the development of the table are as follows: For a defined frequency distribution, the random standard uncertainty of the sample mean, sX, can be used to define the probable interval about the sample mean that is expected to contain the population mean with a defined level of confidence. A quick and easy way to numerically calculate the sensitivity coefficients of the independent m parameters is to develop a table using a spread- sheet program on the personal computer.

In general, correlated systematic standard uncer- wtainties can either decrease, increase, or have no experimental variables.

Journal of Engineering for Power: Case 3, where a partial overlap of the uncertainty intervals exists, is the most difficult wto analyze. A posttest uncertainty analysis serves to 1 validate the quality of the test result by demonstrating compliance with test requirements; 2 facilitate communication of the quality of the test result to all parties to the test; and 3 facilitate interpretation of the quality of the test by those using the test result.

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Those evaluated with statistical methods are classified as Type A, while those, which are evaluated by other means, are classified as Type B. The partial correlation for the pressure measurement must be derived from the elemental uncertainties. The three intervals are: Thus two future units from the sampled population will z be located in the interval: For example, if experience indicates that timeto-time and test apparatus-to-apparatus variations are significant, a test design that averages multiple test results on one rig or for only one day may produce optimistic random uncertainty estimates compared to testing several rigs, each monitored several times over a period of several days.

The assumption is made that there are no common uncertainty sources between Yj and Xj no correlation between the bYj and bXj systematic standard uncertainties. Example adapted from unceftainty In successive measurements of the parameter, the values of these elemental random error sources change resulting in the random scatter evident in the successive measurements.

If yncertainty can be done then it should be, but if not then the method of para. If the nature of an elemental error is fixed over the duration of the defined measurement w process, then the error contributes to the systematic uncertainty.

Engineers have come to appreciate that few things in life are known exactly. The Standards Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate.

By definition, the adiabatic efficiency of a compressor is the ratio of the work input required to raise the pressure of a gas to a specified value in an isentropic manner to the actual work input.