Efficiency curves

Ionization efficiency curve. Shows the number of ions produced as a function of energy of the electrons, photons, or particles used to produce ionization. 

Fig. 7. Cyclone generalized grade-efficiency curves. The soHd line is for the Lapple cyclone dimension ratios given in Figure 9. The dotted line is theoretical...

Cyclone Efficiency. Most cyclone manufacturers provide grade-efficiency curves to predict overall collection efficiency of a dust stream in a particular cyclone. Many investigators have attempted to develop a generalized grade-efficiency curve for cyclones, eg, see (159). One problem is that a cyclone s efficiency is affected by its geometric design. Equation 15 was proposed to calculate the smallest particle size collectable in a cyclone with 100% efficiency (157). 

This equation is for Eigure 9 cyclone dimension ratios. The term the effective number of spirals the gas makes in the cyclone, was found to be approximately 5 for Lapple s system (134). The soHd line grade-efficiency curve of Eigure 7 is also used with Lapple s cyclone, which is a somewhat taller, less compact cyclone than many commercial designs. 

Practically all cyclone performance data have been related to a present cyclone set of geometric ratios. One model for cyclone grade-efficiency curves has been tested against reported commercial cyclone efficiencies (159). A good fit was obtained. 

Typical light output versus current (L—I) and efficiency curves for double heterostmcture TS AlGaAs LEDs lamps are shown in Eigure 8. The ir LED (Eig. 8a) is typically used for wireless communications appHcations. As a result, the light output is measured in radiometric units (mW) and the efficiencies of interest are the external quantum efficiency (rj y. = C y., photons out/electrons in) and power efficiency. As a result of the direct band gap... 

Eig. 8. Light output (—) vs current (L—I) and efficiency curves (-) of double heterostmcture TS AlGaAs LED lamps where the composition of the... 

FIG. 17-39 Single particle collection efficiency curve. Coutiesy of PSRI, Chicago.)... 

FIG. 18 83 Efficiency curve for scale-up of barch clarification data to determine nominal detention time in a continuous clarifier,... 

Typical separation efficiency curves of an air classifier versus particle size are given in Fig. 20-14. The amount of top size in the fines may be very low, but there is typically 10 to 30 percent fines in the coarse product that is, the low end of the cui ve tends to flatten out at 10 to 30 percent. In addition, the separation at the cut size is typically a gradu cui ve. Data of this sort, which are needed to evaluate closed-circuit mill performance, are seldom available. See subsection on characteristics of size classifiers for a testing method. 

FIG. 25-23 Fractional efficiency curves for conventional air-pollution-control devices. [Chem. Eng., 87(13), 83 (June 30, 1980).]... 

Calibrated machine. When brake and pulley or dynamometer methods are not possible, the test motor may be loaded onto a calibrated generator. The efficiency curve of the generator must be available. 

Ixt .s talk about the pump efficiency. Imagine a small pump connected to a garden hose squirting a stream of water across the lawn. You could direct the How from the ho.se up into the air at about a 45-degree angle, and the stream would arc upward and attain its best distance of reach from the nozzle or launch point. The stream of water would attain a specific height into the air and a specific distance. The efficiency curve of a pump is seen as the trajectory or arc of a stream of water. When squirted from a hose, the elevation that attains the be.st distance, when plotted onto the pump curve, is called the best efficiency point (RHP). On the pump curve, it is seen as in Figure 7. ... 

Figure 4-110 depicts an efficiency curve versus velocity ratio for a reaction-type expander. The optimum efficiency will occur at a velocity ratio of. 63. For a velocity ratio considerable greater or less than. 63 a significant efficiency penalty can be expected. Considering the effects on the parameters mentioned above, it is easy to see the importance the velocity ratio has on the performance of the expander. 

A very important analytical tool that is overlooked by many sourcetesting personnel is the microscope. Microscopic analysis of a particulate sample can tell a great deal about the type of material collected as well as its size distribution. This analysis is necessary if the sample was collected to aid in the selechon of a piece of control equipment. All of the efficiency curves for particulate control devices are based on fractional sizes. One would not try to remove a submicron-size aerosol with a cyclone collector, but unless a size analysis is made on the sampled material, one is merely guessing at the actual size range. Figure 32-8 is a photomicrograph of material collected during a source test. 

An equation was developed by the author from the pump efficiency curves in the eighth edition of The GPS A Engineering Data Book. provided by the M. W. Kellogg Co. The curves were found to check vendor data well. The equation admittedly appears bulky, but is easy to use. 

Engineering factors include (a) contaminant characteristics such as physical and chemical properties - concentration, particulate shape, size distribution, chemical reactivity, corrosivity, abrasiveness, and toxicity (b) gas stream characteristics such as volume flow rate, dust loading, temperature, pressure, humidity, composition, viscosity, density, reactivity, combustibility, corrosivity, and toxicity and (c) design and performance characteristics of the control system such as pressure drop, reliability, dependability, compliance with utility and maintenance requirements, and temperature limitations, as well as size, weight, and fractional efficiency curves for particulates and mass transfer or contaminant destruction capability for gases or vapors. 

Figure 2. Example of theoretical collection efficiency curve.

Lynch, A.J., T. C. Rao, T.C., "Influence of Hydrocyclone Diameter on Reduced Efficiency Curves," International Journal of Mineral Processing, 1, 173 (1974)... 

The collection efficiency curve is usually employed to demonstrate the performance of a cyclone. Figure 13.3 shows a typical collection efficiency curve for a cyclone at a particular airflow rate. The size of particles that have a collection efficiency of 50% is usually employed as a simple indication of the separation efficiency of the cyclone, and is known as the cut-off particle size... 

FIGURE 13.3 Typical collection efficiency curve of a cyclone. 

By integrating Eq. (13.35) step by step in time, the particle trajectory of the particle may be obtained. In the integration, the interaction between the particle and the wall may be approximated as being fully elastic however, when the particle hits the sidewall of the cyclone, the particle may be treated as being collected and the computation for the particle may terminated in order to save the computational time that may be required to track the particle to the bottom of the cyclone. If the particle trajectories for a range of particle diameters at different rates of fluid flow through the cyclone are determined, then the particle efficiency curve and the cut-off particle diameter of the cyclone may be obtained. 

It should be noted, however, that the cut size is an idealization. In practice perfect separation does not occur some smaller particles than expected will be present in the underflow whilst some larger than predicted occur in the overflow leading to a blurring of the separation in a grade efficiency curve (Figure 4.23). 

Theoretical representation of the behaviour of a hydrocyclone requires adequate analysis of three distinct physical phenomenon taking place in these devices, viz. the understanding of fluid flow, its interactions with the dispersed solid phase and the quantification of shear induced attrition of crystals. Simplified analytical solutions to conservation of mass and momentum equations derived from the Navier-Stokes equation can be used to quantify fluid flow in the hydrocyclone. For dilute slurries, once bulk flow has been quantified in terms of spatial components of velocity, crystal motion can then be traced by balancing forces on the crystals themselves to map out their trajectories. The trajectories for different sizes can then be used to develop a separation efficiency curve, which quantifies performance of the vessel (Bloor and Ingham, 1987). In principle, population balances can be included for crystal attrition in the above description for developing a thorough mathematical model. 

Dithiiranethione is an isomer of CS3 and its preparation and structure have been drawing much attention [75JCS(P2)559]. In the chemiionization process of CS + CS2 using the molecular beam photoionrzation method, the photoionization efficiency curve of CS3 was observed (80JCP4242). 

Figure 4-5. Efficiency curves for various types of dust collection equipment as of 1969. Only marginal improvements have been made since then. By permission, Sargent, G. D., Chemical Engineering, Jan. 27,1969, p. 130.

Figure 4-46. General efficiency curves, applies specifically to helical entry cyclone dust separators. Courtesy of The Ducon Co.

Figure 4-47. General efficiency curve applies specifically to involute entry cyclone dust separators. Courtesy of American Blow/er Div., American Radiator and Standard Sanitary Corp.

Figure 12-18A. Compressor volumetric efficiency curves for gas with k or n of 1.15. (Used by permission Natural Gasoline Supply Men s Association Data Book, 1957. Origin Ingersoll-Rand Co. All rights reserved.)...

At any constant or steady speed of operation of a compressor, the head-capacity and efficiency curves are characteristic of the impeller and casing design only. These curves that are determined by test can be translated to other reasonable speeds and conditions of operation of the wheel-casing combination of the affinity laws. The operation of the compressor must meet or establish the desired point on the head-capacity-system curve, which requires a combination of controls. 

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