Transmissible turbulent flow

Transition front streamline to turbulent flow 75. 82 Transmissivity 446... 

Ultrasound flowmeters of the transmission type (Fig. 18.11(a)), which are based on the principle that the sound transmission speed will be increased by the flow rate of the fluid, are used in all types of clean, subsonic flows. Doppler flowmeters (Fig. 18.11(b)) rely on echoes from within the fluid, and are thus only useful in dirty flows that carry suspended particles or turbulent flows that produce bubbles. Ultrasound flowmeters are nonintrusive devices, which can often be retrofitted to existing duct or pipe systems. 

Raman spectroscopy s sensitivity to the local molecular enviromnent means that it can be correlated to other material properties besides concentration, such as polymorph form, particle size, or polymer crystallinity. This is a powerful advantage, but it can complicate the development and interpretation of calibration models. For example, if a model is built to predict composition, it can appear to fail if the sample particle size distribution does not match what was used in the calibration set. Some models that appear to fail in the field may actually reflect a change in some aspect of the sample that was not sufficiently varied or represented in the calibration set. It is important to identify any differences between laboratory and plant conditions and perform a series of experiments to test the impact of those factors on the spectra and thus the field robustness of any models. This applies not only to physical parameters like flow rate, turbulence, particulates, temperature, crystal size and shape, and pressure, but also to the presence and concentration of minor constituents and expected contaminants. The significance of some of these parameters may be related to the volume of material probed, so factors that are significant in a microspectroscopy mode may not be when using a WAl probe or transmission mode. Regardless, the large calibration data sets required to address these variables can be burdensome. 

A flowing coaxial region of air. such as on an actual engine, has not yet been investigated on the partially confined initiator geometry, but it is to be evaluated on the next phase of this project. The presence of turbulence and increased kinetic energy should improve the overall transmission properties. Additional computational results will evaluate these effects in conjunction with the experimental test program. 

Turbulent stresses are determined by standard and modified K-e models of turbulence. For determination of flow field near the wall the method of parietal functions was used. Rates fields and pressures were corrected in the course of calculation according with SIMPLE-C algorithm. Diffusion of indicator was modeled as transmission of scalar introduced in less space of time in comparison with its average residence time in apparatus at fixed rate fields and turbulence parameters. 

In the absence of promoters, the transmission from laminar flow to a turbulent regime will again depend on the velocity of movement of the solution and its kinematic viscosity, i.e. on the Reynolds number. In the case of the rotating disc system, the Reynolds number is defined by the equation... 

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