Abstract:The multihole pressure probes are widely used to determine flow velocity vectors and pressures in the fluid machinery fields due to their robustness, convenience, and economy in flow measurement. Accuracy and fast calibration of a multihole pressure probe is very important. In this article, a multihole pressure probe automatic calibration system is developed. The hardware device mainly consists of computer, motion control equipment and data acquisition (DAQ) equipment, and the software program is developed usi… Show more
“…The total pressure probes were calibrated using a pressure probe calibration system. 19 Each pressure signal measured by the total pressure probes or the static pressure measuring holes was converted into a voltage signal by a high-accuracy pressure transducer. The error of the measured total pressure was determined by the probes and the transducer, whereas that of the static pressure depended only on the transducer.…”
Section: Test Facility and Instrumentationmentioning
confidence: 99%
“…The total pressure probes were calibrated using a pressure probe calibration system. 19 Figure 1.Performance test system.…”
Section: Experiments and Validation Of The Numerical Calculation Schemementioning
A volute is the only circumferential asymmetric component in a centrifugal compressor, and thus, it should account for the circumferential asymmetry of the flow in a vane diffuser. This study performs a transient numerical analysis to investigate the effect of a volute on the flow in the vane diffuser of a centrifugal compressor under three operating conditions (near-stall, middle, and high mass flow). We compare numerical and experimental performance of the compressor, including polytropic efficiency, total pressure ratio, and unsteady pressure on a diffuser vane. The numerical scheme is proven valid owing to the fact that the numerical and experimental results considerably agree well with each other. Under middle and high mass flow conditions, the time-averaged static pressure recovery and the total pressure loss coefficients for all the diffuser passages indicate that the performance of the passages near and upstream of the volute tongue is affected negatively by the volute, whereas that of the passages downstream of the volute tongue is less affected. Under near-stall condition, the performance of all the passages is disturbed, and the diffuser passage marked as DP 3 demonstrates the worst performance. Investigation on the time-averaged aerodynamic forces, loading, and pressure on the vanes yields results that are consistent with those of the investigation on the performance of the passages. The harmonics with 0.5f b and f b , which are included in the unsteady loading and pressure on the pressure and suction sides of the vanes, are dominant, where f b is the impeller main and splitter blades passing frequency. Their amplitude values increase as mass flow deviates from the middle mass flow condition. Under middle and high mass flow conditions, the harmonic with 0.5f b is affected more negatively because of the larger amplitude on the vanes near and upstream of the volute tongue than those downstream, whereas the harmonic with f b is less affected by the volute. Under the nearstall condition, the transient vorticity fields along with the harmonics of 0.5f b and f b are investigated to evaluate the performance of the diffuser passages. DP 3, which is located at approximately 90 downstream of the volute tongue, suffers the strongest flow deterioration and is inferred to stall first. Further researches for designing more matching diffuser/volute combination will be performed by referring this study.
“…The total pressure probes were calibrated using a pressure probe calibration system. 19 Each pressure signal measured by the total pressure probes or the static pressure measuring holes was converted into a voltage signal by a high-accuracy pressure transducer. The error of the measured total pressure was determined by the probes and the transducer, whereas that of the static pressure depended only on the transducer.…”
Section: Test Facility and Instrumentationmentioning
confidence: 99%
“…The total pressure probes were calibrated using a pressure probe calibration system. 19 Figure 1.Performance test system.…”
Section: Experiments and Validation Of The Numerical Calculation Schemementioning
A volute is the only circumferential asymmetric component in a centrifugal compressor, and thus, it should account for the circumferential asymmetry of the flow in a vane diffuser. This study performs a transient numerical analysis to investigate the effect of a volute on the flow in the vane diffuser of a centrifugal compressor under three operating conditions (near-stall, middle, and high mass flow). We compare numerical and experimental performance of the compressor, including polytropic efficiency, total pressure ratio, and unsteady pressure on a diffuser vane. The numerical scheme is proven valid owing to the fact that the numerical and experimental results considerably agree well with each other. Under middle and high mass flow conditions, the time-averaged static pressure recovery and the total pressure loss coefficients for all the diffuser passages indicate that the performance of the passages near and upstream of the volute tongue is affected negatively by the volute, whereas that of the passages downstream of the volute tongue is less affected. Under near-stall condition, the performance of all the passages is disturbed, and the diffuser passage marked as DP 3 demonstrates the worst performance. Investigation on the time-averaged aerodynamic forces, loading, and pressure on the vanes yields results that are consistent with those of the investigation on the performance of the passages. The harmonics with 0.5f b and f b , which are included in the unsteady loading and pressure on the pressure and suction sides of the vanes, are dominant, where f b is the impeller main and splitter blades passing frequency. Their amplitude values increase as mass flow deviates from the middle mass flow condition. Under middle and high mass flow conditions, the harmonic with 0.5f b is affected more negatively because of the larger amplitude on the vanes near and upstream of the volute tongue than those downstream, whereas the harmonic with f b is less affected by the volute. Under the nearstall condition, the transient vorticity fields along with the harmonics of 0.5f b and f b are investigated to evaluate the performance of the diffuser passages. DP 3, which is located at approximately 90 downstream of the volute tongue, suffers the strongest flow deterioration and is inferred to stall first. Further researches for designing more matching diffuser/volute combination will be performed by referring this study.
“…LabVIEW is the most widely used , fastest-growing, most powerful virtual instrument development software, using data flow diagram makes the program simple and clear, give full play to the advantages of graphical programming environment, shorten the development cycle, eliminate the virtual instrument of virtual instrument programming of complex process. Based on the LabVIEW, the author develops a set of space controller measurement system [2].…”
In order to solve the difficulty in testing space controller, a general measurement system is designed and integrated. Based on LabVIEW, the multi loops model of producer/consumer is chosen to program which makes the interaction and sharing of data came true. Using the structure of state machines, the measurement task is completed by the measurement system efficiently and reliably. Following the MIL-STD-1553B bus protocol, completed 1553B communication test between host computer and space controller. Through the process of the noise reduction, the noise of the experimental data is effectively eliminated or reduced so that the measurement accuracy is improved. The space controller measurement system that is based on LabVIEW makes high-speed data acquisition, real-time processing, synchronous display and parallel control requirements come true, which has generality and extension as well.
“…While a data acquisition method such as laser Doppler velocimetry (LDV) is typically used to measure velocity fields it does complicate the portable nature with issues of safety and calibration. Therefore, a slightly more intrusive seven-hole probe method was to be explored [11]. Combined with a three-dimensional traversing system this method would be able to measure multi-component velocities around scale models.…”
She joined Minnesota State University, Mankato as a post-doctoral teaching fellow for 2015-16 Acedemic Year. She is still serving at the same institution as an Assistant Professor at the Department of Mechanical and Civil Engineering. Yilmaz Wodzinski offers a broad range of courses to engineering program students and conducts research on renewable energy, water treatment and water resources.
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