Study on the Properties of Aerodynamic Reference Sound Sources

Towards the establishment of traceability in sound power in airborne sound, the present study focuses on the dissemination procedure. Aerodynamic reference sound sources were studied as potential transfer standards. Initially, the sources were examined in the up-to-present requirements. The core of the study is the correction required for the transition from calibration to in situ conditions. The influence of atmospheric pressure, ambient temperature and fan rotation speed was investigated and the corresponding correction was determined. A comparison to an existing correction was also performed. Near field effects were another part of the study. The related uncertainty was estimated in a transparent approach. The dependency of the uncertainty on the in situ and calibration condition values is also presented.

High-Efficiency Remote Measurement of Pipe Defect Using RF/UT Technologies: A Theoretical Analysis Part One — Straight Beam UT

This analysis has established a new hybrid RF/UT system for non-destructive testing of pipe walls for pipe wall thinning (PWT) in order to predict location, and enable measurement of the depth of defect by combining the group velocity method and calibration condition. A simulation of microwave (MW) behavior in a 91% brass waveguide (762mm pipe, Young’s Modulus 102KN/mm2) was developed using Computer Simulation Technology (CST). The model included a frequency band of 1.283GHz for the TMnm mode (TM01 and TM21), with a sweeping frequency from 0.70GHZ to 2.00GHz. The model includes 14 instances of full-circumferential PWT, regularly spaced along the length of the waveguide with step-width of 50.8mm on center. For each we have modeled four cases of increasing PWT (5.08mm, 10.16mm, 15.24mm and 20.32mm). Considering the measurement with MW as a prediction of the location of the PWT, rather than a measurement, we can guide a straight-beam UT probe to the position predicted by MW, and use the appropriate signal velocity ultrasound to accurately measure the depth to defect from the outer surface of the pipe. The straight beam UT is found to be no better at determining the geometry of the defect than MW, but the accurate depth to defect (DDO) measurement would allow estimation of the volume of the PWT.

Study on Efficiency Character of Axial Internal Combustion Fluid Pump

Integrating traditional engine and plunger pump, a new type power equipment─Internal Combustion Fluid Pump(ICFP) was developed, through which thermal energy can be turned into hydraulic pressure directly. As a main factor affecting ICFP’s performances, efficiency is the basis to design its structure. For three-cylinder axial ICFP, it’s dynamics model was setup, and its efficiency character was studied. The simulating results show that ICFP’s effective thermal efficiency is 37.44% at calibration condition, which is higher than engine-pump system by 23.06%. For the three-cylinder ICFP, the effective thermal efficiency experiments are done. Errors are within 5%, and it proved that the simulation results are correct.

Determine Weight of Hot Metal Car Using Strain Gage Method

In certain situations, train car containers that carry hot metal have been overfilled, which necessitated the replacement of very costly car parts. Therefore, it is desirable to predict the amount of fluid needed at all times in order to know when to divert the flow of molten steel from the car. This study showed that the level of fluid in a container can be controlled even when the amount of fluid inside the container is not visible. When strain gages are effectively installed they can be used to continuously calculate the weight of a system as the strain increases, although only the final total weight is of concern. Strain gages can be positioned in safe locations on the spanner bolster of a hot metal car. The gages are installed such that the thermal and axial strains cancel out, ultimately leaving only the value for the weight of the loaded car. Once the gages are installed, they are calibrated when the system is full. For all subsequent loading periods, the strain gages report a linear strain increasing until it is equal to the original full calibration value. This then signals the operator to divert the flow of steel. If the inside of the container deteriorates over time, the strain that governs the shutoff remains the same although the fluid level is slightly lower. In the event of skull (leftover steel in the container), the maximum strain remains the same and the final volume is lower than the initial calibration condition. The objective in all cases is to avoid overflow of fluid from the car. This investigation showed that the amount of fluid in a train car that carries molten steel can be known at all times during the filling process. It is supported with manual calculations, finite element analyses, and laboratory experiments.