Rotor technique

Nozzle port size is also selected to accomodate desired spray rate and viscosity. The position of the nozzle is very significant. In top spray coating operations, the nozzle is positioned to spray liquid counter currently to the flow of product (see Figure 3). In the Wurster system, the nozzle sprays concurrently with the well organized flow of substrate (see Figure 4), and in the rotor technique, the nozzle sprays concurrently in the spiralling bed of product (see Figure 5). 

Using the Surface Growth method, oriented UHMWPE ribbons with tensile moduli greater than 100 GPa and tensile strength greater than 3 GPa were achieved. However, this process is not practical due to its low production rate and non-uiuform ribbon thickness So the rotor technique was developed with imlimited tape width, as shown in Fig. 10.6 (Mackley, 1985 Zwijnenburg and... 

Mackley, M. R. 1985. Oriented Polymer Film-Rotor Technique. 

In co-operation with LM Glasfiber, a complete section of a rotor blade was produced with a number of well defined defects in order to perform an initial sensitivity test by means of ultrasound, vibrations techniques and real-time radiography. Based on the results of this initial test it was found that automated ultrasonic inspection was the best suited teclmique. In co-... 

Today the coin-tap test is a widely used technique on wind turbine rotor blades for inspection of thin GFRP laminates for disbonded and delaminated areas. However, since the sensitivity of this technique depends not only on the operator but also on the thickness of the inspected component, the coin-tap testing technique is most sensitive to defects positioned near the surface of the laminate. Therefore, there has been an increasing demand for alternative non-destmctive testing techniques which is less operator dependent and also more sensitive to delaminations and disbonded areas situated beyond thicker GFRP-laminates. 

Another automated approach to kinetic analyses is the centrifugal analyzer, a partial cross section of which is shown in Figure 13.9. In this technique the sample and reagents are placed in separate wells oriented radially around a circular transfer disk attached to the rotor of a centrifuge. As the centrifuge spins, the... 

Turbine-Blade Cooling The turbine inlet temperatures of gas turbines have increased considerably over the past years and will continue to do so. This trend has been made possible by advancement in materials and technology, and the use of advanced turbine bladecooling techniques. The olade metal temperature must be kept below 1400° F (760° C) to avoid hot corrosion problems. To achieve this cooling air is bled from the compressor and is directed to the stator, the rotor, and other parts of the turbine rotor and casing to provide adequate cooling. The effect of the coolant on the aerodynamic, and thermodynamics depends on the type of cooling involved, the temperature of the coolant compared to the mainstream temperature, the location and direction of coolant injection, and the amount of coolant. 

The existence of unbalance in a rotor system may be in continuous form or discrete form, as shown in Figure 17-2. Ascertaining an exact distribution is an extremely difficult, if not impossible, task by today s techniques. 

Static techniques to determine unbalance can be performed by setting a rotor on a set of frictionless supports the heavy point of the rotor will have a tendency to roll down. Noting the location of this point, the resultant unbalance force can be found, and the rotor can be statically balanced. Static balancing makes the center of gravity of the rotor approach the centerline of two end supports. 

The best balance technique for high-speed flexible rotors is to balance them not in low-speed machines, but at their rated speed. This is not always possible in the shop therefore, it is often done in the field. New facilities are being built that can run a rotor in an evacuated chamber at running speeds in a shop. Figure 17-4 shows the evacuation chamber, and Figure 17-5 shows the control room. 

One is the so-called A-plane approach. This approach states that only A-planes are necessary for a rotor system running over Ncritical speeds. The other technique, called the (N + 2)-plane approach, requires two additional planes. These two additional planes are for the two-bearing system and are necessary in this school of balancing. 

The A-plane is based on the concepts of the modal technique. From Equation (17-5), there are N principal modes that need to be zero for the perfect balance of a rotor, which runs through Mh critical speed. Thus, A-planes located at the peaks of the principal modes will be enough for cancelling these modes. From the point of view of residual forces and moments at the support bearings, (N + 2)-planes are better than A-planes. 

For new rotors, where the elements have not yet been put on the rotor, other techniques can be used. First, the components can be individually balanced on a precision mandrel. Precision means that the runout is a few tenths of a mil (.001 inch). The runout high spot should be scribed on the mandrel. The new component now can be reasonably well-balanced. As the component is removed from the mandrel, the mandrel mark should be transferred to the component. When all the components are completed, the shaft is checked for runout. The high spot should be marked. As the components are stacked onto the shaft, the marks on the shaft are aligned with those transferred to the component. This works well with keyless rotors (no key between shaft and component). Experience has shown ihat in most cases with keyless rotors when the stacked rotor is put in the balance machine and checked, the residual unbalance is within the acceptable tolerance. If not, the rotor must be unstacked and the problem located. It must be remembered, however, if the components were properly balanced and the rotor comes out with unbalance, there must be a proh-... 

With this technique the motor has a wound rotor brought out to slip rings and an external resistance is connected into the rotor circuit. This resistance usually consists of a series of resistor banks, which are switched out progressively in a number of steps as the motor accelerates. The number and rating of each step is chosen so that starting current and motor torque are within requirements. 

Science of rotor-bearing-support system design and operation. Predictive maintenance technique that uses spectrographic, wear particle, ferrography, and other measurements of the lubricating oil as a diagnostic tool. 

For best results, balance the rotor on its own shaft rather than on a balancing shaft. This may require some rotors to be balanced in an overhung position, a procedure the balancing shop often wishes to avoid. However, it is better to use this technique rather than being forced to make... 

The choice of scale-up technique depends on the particular system. As a general guide, constant tip speed is used where suspended solids are involved, where heat is transferred to a coil or jacket, and for miscible liquids. Constant power per unit volume is used with immiscible liquids, emulsions, pastes and gas-liquid systems. Constant tip speed seems more appropriate in this case, and hence the rotor speed should be 0.66 Hz. The... 

In summary, the NLE technique offers a concepmally new approach to observe NFS. Existing limits for time resolution could be overcome by a microfocused synchrotron beam (as planned for PETRA III) and by detectors with high spatial resolution and background from SAXS could be suppressed by employing high-energy transitions and crystalline sapphire as rotor material. 

In this chapter, we first present a brief overview of the experimental techniques that we and others have used to study torsional motion in S, and D0 (Section II). These are resonant two-photon ionization (R2PI) for S,-S0 spectroscopy and pulsed-field ionization (commonly known as ZEKE-PFI) for D0-S, spectroscopy. In Section HI, we summarize what is known about sixfold methyl rotor barriers in S0, S, and D0, including a brief description of how the absolute conformational preference can be inferred from spectral intensities. Section IV describes the threefold example of o-cholorotoluene in some detail and summarizes what is known about threefold barriers more generally. The sequence of molecules o-fluorotoluene, o-chlorotoluene, and 2-fluoro-6-chlorotoluene shows the effects of ort/io-fluoro and ortho-chloro substituents on the rotor potential. These are approximately additive in S0, S, and D0. Finally, in Section V, we present our ideas about the underlying causes of these diverse barrier heights and conformational preferences, based on analysis of the optimized geometries and electronic wavefunctions from ab initio calculations. 

Microwave spectroscopy can determine the magnitude of V6 in S0 but not the sign, since the potential well is too small to localize even the m = 0 wavefunction. S, <— S0 absorption spectra of cold molecules with 1 cm"1 resolution can reveal the magnitude of V6 in S, a technique pioneered by Ito and coworkers.4 Pratt and coworkers7 and Miller and coworkers8 have made major contributions to the high-resolution optical spectroscopy of rotor-containing molecules. 

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