Air flow increase

Figure 6. Mass fraction of theoretical contaminant mass remaining vs. time for various values of the hydrodynamic dispersivity, a. Atmospheric pressure changes at land surface cause advective subsurface air flow, increasing dispersivity which significantly affects the rate at which volatile contaminants escape from a layer. Reprinted from Auer et al. (1996), Copyright 1996, pg. 157, with permission from Elsevier Science.

Steam production increases when the process air flow increases. 

Fan operation is indicated on a performance curve, as shown in Fig. 19.3. The head developed by the fan is equivalent to 5 or 10 inch of water. As the fan air flow is pretty constant, the fan s head is also constant. Another way of stating this is to say that as a tube bundle fouls, the resistance to air flow increases. This reduces the air flow through the bundle, but the pressure loss of the air flow through the tube bundle does not change. 

Setting the blade pitch cannot be done with great precision, and it s not too critical. I once increased the blade pitch from 15° to about 22°. Air flow increased by only 5 percent measured by the increased amperage load on the motor driver. 

It seemed to me that air flow increased by some amount that 1 did not measure. The operators reported that cooling had been increased. 

Some empirical equations to predict cyclone pressure drop have been proposed (165,166). One (166) rehably predicts pressure drop under clean air flow for a cyclone having the API model dimensions. Somewhat surprisingly, pressure drop decreases with increasing dust loading. One reasonable explanation for this phenomenon is that dust particles approaching the cyclone wall break up the boundary layer film (much like spoiler knobs on an airplane wing) and reduce drag forces. 

This invention relates generally to light weight covers used to increase the aerodynamic properties of wheels. More specifically, the present invention relates to covers for wheels capable of creating an aerodynamic effect by reducing the friction or drag across the surface of a wheel created by air flow. 

Testers are available to measure the permeabihty and compressibiUty of powders and other bulk soflds (6). Erom such tests critical, steady-state flow rates through various outlet sizes in mass flow bins can be calculated. With this information, an engineer can determine the need for changing the outlet size and/or installing an air permeation system to increase the flow rate. Furthermore, the optimum number and location of air permeation levels can be deterrnined, along with an estimate of air flow requirements. 

A more obvious energy loss is the heat to the stack flue gases. The sensible heat losses can be minimized by reduced total air flow, ie, low excess air operation. Flue gas losses are also minimized by lowering the discharge temperature via increased heat recovery in economizers, air preheaters, etc. When fuels containing sulfur are burned, the final exit flue gas temperature is usually not permitted to go below about 100°C because of severe problems relating to sulfuric acid corrosion. Special economizers having Teflon-coated tubes permit lower temperatures but are not commonly used. 

The cross-flow-tower manufacturer may effec tively reduce the tower characteristic at very low approaches by increasing the air quantity to give a lower L/G ratio. The increase in air flow is not necessarily achieved by increasing the air velocity but primarily by lengthening the tower to increase the air-flow cross-sec tional area. It appears then that the cross-flow fill can be made progressivelv longer in the direction perpendicular to the air flow and shorter in the direction of the air flow until it almost loses its inherent potential-difference disadvantage. However, as this is done, fan power consumption increases. 

The fuel flows at right angles to the air flow. Only a small amount of air is fed at the front of the stoker, to keep the fuel mixture rich, but as the coal moves toward the middle of the furnace, the amount of air is increased, and most of the coal is burned by the time it gets halfway down the length of the grate. Fuel-bed depth varies from 100 to 200 mm (4 to 8 in), depending on the fuel, which can be coke breeze, anthracite, or any noncaking bituminous coal. 

The Steam Injection Cycle Steam injection has been used in reciprocating engines and gas turbines for a number of years. This cycle may be an answer to the present concern with pollution and higher efficiency. Corrosion problems are the major hurdle in such a system. The concept is simple and straightforward Steam is injected into the compressor discharge air and increases the mass flow rate... 

For NO control only, steam is injected into the combustor directly to help reduce the primary zone temperature in the combustor. The amount of steam injected is in a ratio of 1 1 with the fuel. In this cycle, the steam is injected upstream of the combustor and can be as much as 5-8 percent by weight of the air flow. This cycle leads to an increase in output work and a shght increase in over l efficiency. Corrosion problems due to steam injection have been for the most part over-... 

Oil coolers either dissipate the heat into a vv ater stream or the air. Water coolers (Fig, 29-85) are significantly more compact, but a supply of vv ater is required. Air coolers (Fig, 29-86) are large and require a fan that increases the air flow ov er the cooling fins,... 

As can be seen from Figs. 7.58 and 7.59, the amount of air in the convection flows increases with height, due to entrainment of the surrounding air. The amount of air transported in a natural convection flow depends on the temperature and the geometry of the surface or source and the temperature of the surrounding air. Because the driving force in convection flows... 

Figure 7.73 shows a plume in an open environment. The hot air from the source entrains ambient air into the convection current (the plume), thus making the air volume flow increase with height. 

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