Inlet bells

Gas turbine eompressor inlet bell-mouth pressure differential versus air flow rate... 

Inlet bells or boxes Aerodynamically shaped inlet ducts for a fan. 

The inlet bell may be arranged in several ways or attached by different methods, but generally it is dieformed to contours that direct the air into the entrance of the wheel, ft seals with an overlap of the wheel shroud over the inlet bell. 

The inducer seen in Fig. 7 was a double helix vane convolution of variable pitch. The optimum degree of prerotation at the inducer inlet could only be speculated. An inlet bell was therefore provided with guide vanes for modification, as previously discussed. 

Figure 2 is a cross section view of one of the model pumps tested in liquid nitrogen and liquid hydrogen. This is a model of a pump designed to be mounted within a dewar, with its inlet bell, shown at the very bottom of the unit, at the bottom of the dewar,... 

Figure 3 is the assembled model pump. The stemlike projection at the top of the unit was used to afford a magnetic rpm pickup, and mounting, and an extension shaft for motor tests. An exploded view of this model is shown in Figure 4. At the top row are the motor housing, impeller, inducer, volute and inlet bell, all made of a high strength aluminum alloy. Below this, at each side of the rotor, are the ball bearings of 440-C stainless. These used micarta ball separators. At the bottom is the shaft, which was 304 stainless steel.

Net Positive Suction Head was also measured directly using the vapor bulb versus static head method devised by NBS, This is shown to the left of the inlet bell. 

Fortunately we had instrumented the metal of the inlet bell for differential temperatures and also thermally isolated it from the rest of the pump. This showed a slight measured cooling referenced to ambient liquid. 

Tube ends may be projecting, flush, flared, or beaded (listed in order of usage). The flare or bell-mouth tube end is usually restricted to water sei vice in condensers and serves to reduce erosion near the tube inlet. 

A suction bell on the inlet of a vertical pump (or the inlet pipe of the suction side of a horizontal pump) is not necessary as far as pump or sump operation is concerned. If a bell is omitted, the entrance losses due to flow will be higher ith only a straight pipe, and this must be considered in pump operation. An economic comparison vsill help decide the value of the bell. Strainers should not be placed on suction bells unless this is the only arrangement. Inlet water should be screened with trash racks, bars and screens to keep the sump free of debris. 

Submergence of the inlet pipe column or bell inlet below the water level is necessary for good operation and to prevent vortexes and entrained air. The minimum submergence as recommended by the manufacturer must be maintained at all Limes. Generally, for 70°F w ater, each 1000 feet of elevation above sea level adds 14 inches to the... 

Reay WG, Gallagher DL, Simmons GM (1992) Groundwater discharge and its impact on surface water quality in a Chesapeake Bay inlet. Water Res Bull 28 1121-1134 Santschi PH, Li YH, Bell J (1979) Natural radionuclides in the water of Narragansett Bay. Earth Planet Sci Lett 45 201-213... 

Carry out the ozonisation in a thin-walled gas wash-bottle (capacity 400 c.c.) with an inlet tube widened out to a bell shaped opening or twisted to a spiral. Connect the bottle to the ozoniser by bending the inlet tube of the former at a right angle so that it can be inserted into the delivery tube of the ozoniser, which is fitted with a mercury seal. 

The reason illustrates the true nature of the shell-and-tube heat exchanger. It is a compromise between an ideal heat-transfer configuration and practical mechanical limitations. In this case, the difficulty is preventing leakage around the longitudinal baffle. Such leaks permit the shell-side fluid to short-circuit the tube bundle that is, a percentage of the inlet flow, may flow directly to the outlet nozzle. In extremely serious cases, I have seen the bell head (shown in Fig. 19.8) 100°F colder than the shell-side outlet temperature. 

Since the numerical values of TL and YL are dependent on the heat exchanging capacity (as shown by equation 3.106), the quantity on the right-hand side of equation 3.110 may be displayed as a function of the inlet temperature to the bed, T0, with T as a parameter. The three bell-shaped curves in Fig. 3.30 are for different values of T and each represents the locus of values given by the right-hand side of this equation. The left-hand side of the equation may be represented by a straight line of unit slope through the point (rCi, 0). The points at which the line intersects the curve represent solutions to equation 3.110. However, we seek only a stable solution which coincides with a high yield. Such a solution would be represented by... 

Dirt and moisture are the worst enemies of the performance of all PD gas meters, so inlet filtering should be used when indicated. Pressure and temperature should either be controlled or compensated. The testing (or proving, as it is called in the gas utility industry) of gas meters is usually done by an accurately calibrated "bell" of cylindrical shape that is sealed in a tank by a suitable liquid. The lowering of the bell discharges a known volume of air through the meter under test. Other standards used to calibrate gas meters are calibrated orifices and critical flow nozzles. These devices compare rates of flow rather than fixed volumes. 

After cooling the electrodes and inletting an air in the bell jar, a soot is removed from the chamber walls, weighed on an analytic balance and filled with toluene. After storing the soot in toluene for several days, we measured the transmission spectrum of the mixture with a SF-26 spectrophotometer. Then the colored mixture is poured out, the residual toluene is evaporated at the temperature T = 500 K from the soot and it is weighed once again. The relative content of fullerens in the soot is measured from these data [2,3]. 

A — Brine inlet, B — Bell-jars, C — Pipes interconnecting individual bells, D — Chlorine outlet, E — Main brlno feed pipe, F — Caustic solution drain, G — Concrete tank. 

If the fluid flows into the pipe through a bell-shaped inlet section as shown in Figure 4.25, the losses in this inlet section will be small. In this case, if po is taken as the pressure ahead of the inlet as shown in Fig. 4.26 and p, is the pressure on the inlet plane then Bernoulli s equation applied across the inlet gives ... 

Figure 20.23 Schematic of inlet-outlet configuration of the bell jar type of reactor. Adapted from Ref 4.

A tube v/ith a bell-mouth inlet configuration is subjected to 8 kW/m uniform vrall heat flux. The tube has an inside diameter of 0.0158 m and a flov/ rate of 1.32 X 10 " m%. The liquid flowing inside the tube is ethylene glycol-P distilled v/ater mixture with a mass fraction of 0,34. The properties of the ethylene glycol-distilled water mixture at the location of interest are Pr = 11,6, V- 1.39 X 10 m /s and 1.14. Determine the fully developed... 

SOLUTION A liquid mixture flowing in a tube is subjected to uniform wall heat flux. The friction coefficients are to be determined for the bell-mouth and square-edged inlet cases. 

From Table 8-6, we see that for a bell-moufh inlet and a heat flux of 8 kW/m the flov is in the transition region. Therefore, Eq. 8-81 applies. Reading the constants A, B, and C and nr, /rr, m3, and m from Table 8-5, the friction coefficient is determined to be... 

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