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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The steps in the development of the table are as follows: Uncertainties in Relative Terms for the Calibrated Case.
ASME PTC – Test Uncertainty
It is seen that for the given sample of 5, the confidence interval to contain the population w mean is appreciably smaller than both the tolerance interval and the prediction interval. For situations in which the frequency distribution and degrees of freedom are unspecified, a normal distribution and large degrees of freedom are often assumed. Possible sources of this special data include a interlaboratory or interfacility tests; and b comparisons of independent measurements that depend on different principles or that have been made by independently calibrated instruments; 19.11 example, in a gas turbine test, airflow can be measured with an orifice or a bell mouth nozzle, or computed from compressor speed-flow rig data, turbine flow parameters, or jet nozzle calibrations.
The compressor was operated at normal, steady-state conditions for two hours prior to the test and for one hour during the uncertaintyy. Data from the loss coefficient test are summarized in Tables Once the questions to be answered have been clearly stated, it should be easy to decide upon the correct intervals. The approach will be to relate the deviations w in r X1, X2.
ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心
The second test is then run in the same facility with the design change and hopefully with instruments, setups, and calibrations identical to those used in the first test. The probability of not rejecting a bad data point is not fixed. Example adapted from : Journal of Thermophysics and Heat Transfer, 7: The term sc in eq. The uncertainty interval for c may be calculated as follows: If flowmeters 1, 2, and 3 are calibrated against the same standard, and flowmeter 4 is calibrated against a different standard, the systematic awme uncertainty for z is larger than if all the meters had been calibrated against different standards Case 1.
Tets Between Calibrated and Uncalibrated Cases. The elemental systematic sources. Prediction intervals are also required by the typical customer who purchases one or a small number of units of a given product and is concerned with predicting the performance w of the particular units he has purchased in contrast to the long-run performance of the process from uncetainty the sample has been selected.
An automotive test facility may only be able to test at specified altitudes and speeds, and the effects at other altitude 19.1 may need to be extrapolated.
The American Society of Mechanical Engi.
Association, 65, December, The statistical equations used to assess variations between tests are similar to those discussed in z para. Attempting to identify all of the elemen- able, it is often necessary to rely upon engineering tal sources of systematic error for a measurement judgment to quantify the pc of errors asso- is an important step of an uncertainty analysis, ciated with an elemental error source.
The Amer-  Steele, W. These may be such things as conduction, convection, and radiation on a sensor when installed in a gas turbine. The general form of the expression for determining the uncertaijty of a measurement is the rootsum-square of the systematic and random standard uncertainties of the measurement, with this quantity defined as the combined standard uncertainty uX . For example, different Defined Measure- w ment Processes for the same test will result in different estimates of measurement uncertainty.
The resulting averages are presented in Uncertaintu Undertainty example is nearly identical to that presented H2O. However, for small samples, when combining elemental random standard uncertainties of the mean by the root-sum-square method [see eq. The specific value of this statistic must be selected on the basis ptd the defined confidence level and degrees of freedom associated with the confidence interval.
Since all of the systematic standard uncertainties for Xj and Xnew are correlated, the systematic standard errors are all the same. Journal of Engineering for Power: As discussed in para.
See subsection for a detailed discussion. For small samples, bad data points are hard to identify. Several simplifying assumptions are made for this example: For small degrees of freedom see Nonmandatory Appendix B.
A common digital temperature indicator, with built-in cold junction compensation, was used to measure both the inlet and the exit wtemperatures. With the recent advances in computer systems, the computational resolution uncertainty sources are often negligible; m however, curve-fit error uncertainty can be signifi- cant.
In computing the preceeding sensitivity coefficients, it was assumed that the specific heat ratio is independent of air temperature. 191.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
Fundamentals of Temperature, m Pressure, and Flow Measurements. Case 3, where a partial overlap of the uncertainty intervals exists, is the most difficult wto analyze.
An eloquent treatment of these terms is given by Gerald Hahn  in his paper, which is. By definition, an elemental systematic standard uncertainty is a value that quantifies the dispersion of the at the standard population of possible deviation level. One measurement will not give the true average value directly.