Resonant tubes

Theoretical Analysis of Resonance Tube , The Singer Company, Final Report KD 72-82 (1972) 58) F.J. Valenta, The State of the Art of Navy Pyrotechnic Delays , Expls Pyrots (The Franklin Institute Research Laboratories) 5, Nos 11 12 (Nov-Dec 1972). See also Ref 144, pp 185—95. See also Some Factors Affecting Burning Rates and Variability of Tungsten and Manganese Delay Compositions , Ref 144, pp 157—83. See also Mil Spec for Tungsten Delay Compositions , MIL-T-23132A (June 1972) 59) C.F. Parrish et al, Radiation... 

Phillips, B. R. et al., Combust. Flame, 1979, 35(3), 249-258 Metal powders or fibres ignite in an oxygen-fed resonance tube. 

Background copper levels in seawater have been measured by electron spin resonance techniques [300]. The copper was extracted from the seawater into a solution of 8-hydroxyquinoline in ethyl propionate (3 ml extractant per 100 ml seawater), and the organic phase (1 ml) was introduced into the electron spin resonance tube for analysis. Signal-to-noise ratio was very good for the four-line spectrum of the sample and of the sample spiked with 4 and 8ng Cu2+. The graph of signal intensity versus concentration of copper was rectilinear over the range 2-10 xg/l of seawater, and the coefficient of variation was 3%. 

The gasdynamics of resonance tubes have been analyzed by Sinha (Ref 8). Typical exptly... 

III A. Pavlak, Tapered Resonance Tubes Some Experiements , AlAAJour 8 (3) (1970), 571-72 8) R. Sinha, A Theoretical Analysis... 

The absorption technique employed by Parker [122] is a modified version of the resonance tube described by Knotzel and Knotzel [123], It consists of a Pyrex glass cylinder, 5 cm in diameter and about 75 cm in length. A cylindrical brass piston is used to generate standing waves in the tube. The sound pressure Pn is observed for frequencies near any of the n resonant frequencies / for the tube, and the resonance half-width <5, in Hz, is de-... 

The resonance tube utilized by Henderson and co-workers [124] for measurements of the vibrational relaxation time in N2, 02, and other gases, is encased in lead to suppress wall movements and to permit operation at high pressures. The fjP range is from less than 5 to more than 20,000 Hz/atm. 

In operation, gas flow is converted directly into thermal energy which is used in the initiation process. While the resonance tube theory for the generation of thermal energy is not new, its application in fluidic systems is unique. The device is 0.825 inch long, 0.250 inch in diam and weighs 0.125 ounce Refs 1) EMX Engineering, Inc, 354 Newark-Pompton Turnpike, Wayne, NJ 07470 2) G. Cohn, Edit, Expls Pyrots 7(4), (1.974)... 

Fig. 2.3. Outline of a conventional one-dimensional nuclear magnetic resonance experiment, (a) A sample in a nuclear magnetic resonance tube (b) a magnet into which the sample is placed (c) the outline of a simple experiment (d) the free induction decay (FID), which is Fourier-transformed to a spectrum (e).

It should be noted that the term shock waves refers to a pressure wave of large amplitude that arises from sharp and vioient disturbances when the velocity of wave propagation exceeds the veiocity of sound propagation. Characteristicaiiy, an abrupt change of the medium properties (e.g., pressure, stress, density, particie velocity, temperature, etc.) takes piace in a limited space across the shock wave (Schetz and Fuhs, 1996 Shapiro, 1953 Anderson, 1982 Saad, 1992). In the case described in this chapter, the physicai phenomenon of shock wave is restricted to one-dimensional plane wave propagation, in which properties of air in the resonant tube of the wave generator... 

The instantaneous pressure and velocity distributions along the resonance tube are monitored by piezoelectric transducers and hot-wire thermal anemometer that are connected to the oscilloscope and photo film recorder. These make possible the tuning of the generator to the acoustic resonance by varying the rotational speed of the crankshaft. Also, there is a provision to attach resonance tubes of various lengths and diameters to obtain required amplitudes of pressure and velocity pulsations. 

Unlike pressure, the profile of the velocity pulsation remains practically unchanged along the resonant tube and distortion of the sinusoidal velocity pulsation occurs only at the tube outlet. As shown in Figure 10.3, the amplitude of velocity pulsation decreases sharply with the distance of wave propagation in open air. To take full advantage of the momentum of shock waves, liquid to be dispersed should be fed close to the outlet from the resonant tube, in this case up to about 20 cm. Also, the strongest impact of shock wave due to air velocity might be expected over a distance up to 1 m from the resonance tube. 

Figure 10.4 presents amplitude-frequency characteristics of two different resonant tubes, where the first and second resonance frequencies are clearly identified by the consecutive maxima on the respective curves. 

Figure 10.2 Characteristic of pressure oscillation in the resonance tube.

Expressing the frequency in terms of the crankshaft rpm, the following experimental correlation can be used to calculate the length of the resonant tube and the amplitude of air velocity at the tube outlet ... 

The dispersion of pasty pigments with shock waves was studied experimentally using the shock-wave generator with a resonance tube of 0.033 m. This allows achieving air velocity equal to 163 m/s at 19.8 Hz of the reciprocating movement of the piston. The pasty feed was located 0.05 m from the resonance tube outlet at its axis. Such a distance was found to be optimal over the range from 1.5 to 5 times the tube diameter. 

The length of the resonance tube for the first (maximum) resonance is given... 

Taking Z = 11.0, the maximum diameter of the resonance tube securing... 

To obtain a uniform velocity profile in a drying chamber, the resonance tube and the drying air inlet should be concentric. Hence, the drying chamber is formed as a truncated cone with the inlet diameter D) and the outlet diameter equal to the diameter of the cylindrical drying chamber Dch). For an inlet diameter of 0.2 m, the chamber diameter is thus... 

Figure 31.16 Schematic of the experimental microwave dryer 1 —motor, 2—MW generator, 3—resonance tube, 4— spiral insert (IV section), 5—viewport, 6—quartz drum, 7—spiral insert (I section), 8—water load, 9—condenser, 10— product tank, 11—swivel, 12—slope adjuster, 13—sol tank, 14—distilled water, 15—condensate tank, 16—condensate discharge. (From Bessarabov et ah, 1999.)... 

Fig. 3. Above The laser-driven photoacoustic system, consisting of a COj laser and an intracavity-positioned photoacoustic PA) cell. Ethylene concentrations are detected using three microphones placed on the resonator tube of the PA cell. Below Instead of a PA cell, a HeNe laser is used to measure ethylene concentrations near the plant tissue under normal atmospheric conditions. The deflection of this laser beam beam is monitored with a position-sensitive detector...

As radiation source for the PA measurements an infrared CO2 waveguide laser was used in an intracavity configuration (100 W laser power) (see Fig. 3, above). A small resonant photoacoustic cell is placed inside the laser cavity between the output mirror and the waveguide tube. To reduce the laser beam radius so that no wall effects occur in the photoacoustic cell the laser beam is focused by a ZnSe lens (f = 254 mm) on a flat output mirror (reflectivity 92.1%). To generate the photoacoustic signal a mechanical chopper is placed inside the cavity. The photoacoustic cell possesses a resonator tube (length 100 mm, diameter 6 mm)... 

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