Main nozzle

Figure 17.3 shows a steam turbine with three, rather than one, nozzles. The single, largest, left-hand valve is called the main nozzle. It handles 60 percent of the motive-steam flow. Each of the two smaller nozzles handles 20 percent of the steam. These 20 percent nozzles can be plugged off by a device sometimes called either a horsepower valve, jet valve, speed valve, star (for the handle shape) valve, or port valve. 

Fig. 3 Mass flow rate of ignition nozzle and main nozzle...

The bio-oil from pyrolysis may contain solid residues and is highly viscous. Filtering and pre-heating are necessary before injection in the main nozzle. For the gas turbine tests the following properties were achieved ... 

The gas turbine was started with diesel oil. Then followed a change over of the fuel through the main nozzle from diesel oil to bio-oil. Due to the lower heating value of the bio-oil it was only possible to operate the gas turbine at part load in the dual-fuel-mode. With the mass flows in Fig. 3 the following power levels are calculated and shown in Table 2. 

The mass flow of bio-oil in relation to diesel fuel increases in the main nozzle with 6.5 GPH (gallons per hour) by up to 1.33. The power in the dual fuel mode is reduced to 73 % of the full power in the diesel fuel mode. The reduction is due to the specific limitations of the gas turbine used for the experiments and not inherent in bio-fuel operation. However, for later commercial use further alterations to the fuel system and the nozzle size would be required. 

The same research group also introduced a microfabricated digital wall attachment amplifier [11] for bistable control of flow. An SEM image of a microscale digital wall attachment amplifier formed on PMMA is illustrated in Fig. 6a. The pressure in one of the output ports (opposite to the control port used) is shown in Fig. 6b for various values of the control port pressure. The output pressures were measured at output 2, while the input control pressure was varied at inlet 1. In the experiment, a jet of 330 hPa pressure was supplied through the main nozzle, while the pressures at the control ports were varied from 0 to 12 hPa. The experimental results showed that if the jet was attached to the wall next to a control port, then temporary application of pressure (12 hPa) to that control port guided the jet to the opposite wall. The jet continued to flow along that wall after the removal of the control jet. A minimum supply pressure was needed for the action of this amplifier. The experimental results also showed that the supply pressure had no effect on the pressure recovery (ratio of maximum output to input pressure) and flow recovery (ratio of maximum output to input flow) in this amplifier. 

Microfluidic Devices for Combinatorial Chemistry, Fig. 21 Geometry and nomenclature of a authors simple fluidic valve. The flow from control nozzle inX interrupts the flow from the main nozzle S into the output terminal Y. In the diagram at right, the relative output flow pyo in... 

It is not uncommon to machine flats for branch connections to main nozzles on a distribution forging. A distribution forging can be designed to accommodate multiple nozzles. In this manner a heavier forged nozzle neck can be machined to accommodate the size and shape of the attached connection. These attachments should be provided by the vessel fabricator and the connections tested with the vessel during the standard shop hydrotest. 

The reactor vessel is intended for arranging an in-vessel unit inside. It is a welded cylindrical vessel with an elliptical bottom, two main nozzles and a flanged part. 

The SGs, MCPs, and CPS drives of the VBER-150 and VBER-300 reactor installations are similar [IV-2, to IV-4]. The design and dimensions of the reactor vessels are also similar (excluding the number of main nozzles - two instead four). 

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