Passage area

The axial flow compressors in aero gas turbines are heavily loaded. The aspecl ratio of the blades, especially the first few stages, can be as high as 4.0, and the effecl of streamhne curvature is substantial. The streamline configuration is a function of the annular passage area, the camber and thickness distribution of the blade, and the flow angles at the inlet and outlet of the blades. The shafts on these units are supported on antifriction bearings (roller or ball bearings). 

In common design practice, the riser area, total slot area, and passage area in the annular space under the cap are approximately equal in order to reduce pressure losses caused by expansion and contraction. Gas bubbles issuing from the slots are seldom projected more than about 1 in. from the cap, and a clearance between caps in the range of 1 to 3 in. is usually sufficient to eliminate large amounts of undesirable bubble coalescence. The caps should be spaced evenly over the entire tray. A clearance between the shell and adjacent... 

For steam boilers, fuels are natural gas and blast furnace gas. A large number of small burners (about 30 hp. each) is used for the former. Burners are thoroughly distributed. As with fuel oil, they may be directed either slightly downward toward the rear or may face from the bridge wall toward the front. The combustion space should be large. The air supply is drawn in around the gas jet. High eflSciency is easily possible. For blast furnace gas, use a furnace space of 2 cu. ft. per rated horsepower, 0.8 sq. in. of gas passage area per horsepower and 2 in. blast (based on 6 to 8 in. pressure in main). Provision must be made for removal of dust. With all gas burners, the gas and air supply should be separately controllable. 

Primaiy crushers have a steep cone angle and a small reduction ratio. Secondaity crushers have a wider cone angle this allows the finer product to be spread over a larger passage area and also spreads the wear over a wider area. Wear occurs to the greatest extent in the lower, fine-crushing zone. These features are further extended in cone crushers therefore secondary gyratories are much less popular than crushers, but they can be used as primaries when... 

I, 277 ppm Ce giving an average Ce/La ratio of 4.5. This is intermediate between the ratios in nodules from the Aitutaki Passage (Area K) and the C.C. FZ (Area C) and is compatible with a hydrogenous origin for these cmsts. 

Theoretically process air would scale to a consistent air velocity through the bed to maintain a similar air pressure on or air velocity through the bed. In a perforated pan, the velocity is related to the exhaust air passage area of the pan under the bed and the percentage of open space in the passage area (pan porosity). In addition, the depth of the bed will influence the pressure drop through the bed. Due to variation in the extent that these factors are a concern, an air assessment in this discussion will be limited to the air passage consideration only. 

Since the air passage area will vary with pan coater design and perforated versus non-perforated configurations, the air passage area for each pan will be assumed to be equivalent to a square section of perforated pan surface with sides equal to 1/2 the pan diameter. A 24 in. diameter pan at 300 ftVmin process air would pass air at a velocity of 300 ft/min (300/(24/2/12) = 300). This air flow would translate to 1200 ftVmin in a 48 in. diameter pan (300 ft/min x (48/2/12) = 1200). Be aware that this is based on assumed air passage dimensions and actual dimensions would be applied in an actual scale-up. 

---