Philip Gerhart

Performance Evaluation Using ASME Performance Test Codes

When faced with the question of “how well is this equipment performing and how can I improve its performance?” ASME Performance Test Codes (PTCs) can help guide us to an answer: ASME PTCs provide uniform rules and procedures for conducting and reporting tests of equipment and systems to evaluate plant and component performance.Copyright

Uncertainty Analysis in Fan Testing

The ASME performance test codes require an uncertainty analysis as part of a code test, and some codes require both a pre-test and a post-test uncertainty analysis. ASME PTC-19.1, Test Uncertainty provides the basic approach to conducting an uncertainty analysis. The individual test codes, such as ASME PTC-11, Fans, provide specific guidance for uncertainty analysis of tests of particular equipment or processes. The following issues related to an uncertainty analysis for a PTC-11 fan test are discussed. • Evaluating uncertainties for traverse measurements — Fan testing requires one or more traverses to measure flow rate as well as various pressures, temperatures, and gas composition. Evaluating and propagating the uncertainty associated with traverse point measurements to obtain overall uncertainty is explained. • Evaluating uncertainties for non-traverse measurements — Fan testing also requires the measurement of power input, fan speed, and atmospheric temperature and pressure. Evaluating the uncertainties in these quantities is discussed. • Propagating uncertainties of the measurements into the final results — An analytical method is compared to “dithering” to obtain a sensitivity factor. • Using a pre-test uncertainty analysis to optimize the test design — Examples are provided on how a pre-test uncertainty analysis can be used to reduce the uncertainties of a fan test. The results include results of sample pre-test and post-test uncertainty analyses for fans.Copyright

Reduced Load Fan Performance Testing for Input Power Determination

The ASME Performance Test Code, PTC 11 Fans, is currently undergoing revision. While there are several changes being made, there are also new additions, the most notable of which is a method to measure input power at reduced fan loads. This information is often required to validate a power guarantee; a condition that presents a unique challenge because fan operation needs to be established at a specific flow and pressure rise that can be corrected to guarantee inlet conditions using the fan laws of similarity. Part 1 of this paper outlines a testing procedure to achieve results close to the specified condition. There is a very low probability that any particular test can be performed at the guarantee condition so several tests within acceptable bounds of the specified point are necessary. Part 2 of this paper discusses a multipoint, distance-weighted interpolation method for determining the final result.© 2007 ASME