Testing nozzles

Figure 23.8 presents axiai pressure distributions for two tests for which air-barbotated kerosene was injected through round (test run No. 11) and elliptic nozzles (test run No. 12) located at the base of fin-pylons in the co-flow direction of the main-stream flow. One can conclude from Fig. 23.8 that the combustion-induced pressure rises for elliptic and round nozzles are nearly the same, i.e., mixing and combustion efficiencies practically remain the same for both t q)es of nozzles. 

Prior to World War II the majority of experimental work in the field of sprays concerned itself with Diesel engine injection problems. Sauter (21C) has suggested that the efficiency of atomization is determined by its fineness and uniformity. De Juhasz (2C) has determined the effect of many different variables on the process of spraying. The more important physical factors tested include the pressure drop across the orifice, the viscosity of the liquid, and the density of the air. For the many different nozzles tested, the ratio of orifice length to diameter has little effect. To determine the effect of the density of the air into which the liquid was sprayed, the nozzles were allowed to discharge into an evacuated chamber. Under these conditions good results are still obtained, suggesting little influence of air friction on jet breakup. 

Low Temperature Fuel Spray Nozzle Tests, Air Force Tech Rept. 6099. 

This case is thus in agreement with the findings of Thompson et al. (T2), that for a given two-fluid system heat transfer is practically independent of orifice diameter. This conclusion, though it may apply for the 0.04- to 0.064-in. nozzles tested by Thompson et al, is subject to reservation for larger diameters. The extensive study of Minard and Johnson (M5) reveals a relatively small but appreciable effect of nozzle diameter over the range from 0.04 to 0.86 in. 

E. Bouillon, G. Habarou, P. Spiiet, I. Lecordix, D. Feindel, D. Stetson, G. Ojard, G. Linsey, Characterization and nozzle test experience of a self sealing ceramic matrix composite for gas turbine applications, Proceedings of IGTI/ASME TURBO EXPO Land, Sea and Air 2002, Amsterdam, The Netherlands, June 3-6, 2002. 

A subsequent electroforming on conducting polymers (here PA 12 with carbon black) allows the fabrication of metal microstructures for e.g. spin nozzles test structures (Figure 5, right side) (4). 

Pretests Regarding Droplet Size Determination Using External Nozzle Test Stand... 

RCT are designed to successfully solve a whole number of tasks in nuclear power when testing fuel elements, in aviation and space industry when testing construction materials, nozzles and engine units, turbine blades and parts, in electromechanical industry-cables switching elements, electric motors in defense sphere- charges, equipment in prospecting for research of rock distribution and detection of precious stones in samples. 

Other examples of government and military applications of laser-based profilometry include the evaluation of rocket thruster nozzles to locate and measure flame erosion remote inspection of hypervelocity test track and the measurement of sludge deposits on tube internal surfaces. 

Goldberg and Rubin [Ind. Eng. Chem. Proce.s.s Des. Dev., 6 195 (1967)] showed in tests with a disk spinning vertically to the foam layer that most mechanical procedures, whether centrifugation, mixing, or blowing through nozzles, consist basically of the application of shear stress. Subjecting foam to an air-jet impact can also provide a source... 

When testing to estabhsh the thermodynamic performance of a steam turbine, the ASME Performance Test Code 6 should be followed as closely as possible. The effec t of deviations from code procedure should be carefully evaluated. The flow measurement is particularly critical, and Performance Test Code 19 gives details of flow nozzles and orifices. The test requirements should be carefully studied when the piping is designed to ensure that a meaningful test can be conducted. 

Higher temperatures also require more cooling and, as temperatures increase, the single can or annular combustor design becomes more attractive. The tubo-annular combustor has a more even combustion because each can has its own nozzle and a smaller combustion zone, resulting in a much more even flow. Development of a can-annular combustor is usually less expensive, since only one needs to be tested instead of an entire unit as in an annular or single-can combustor. Therefore, the fuel and air requirements can Be as low as 8-10% of the total requirements. 

The test is carried out by washing down the test enclosures in every direction by means of a standard hose nozzle of 6.3 mm inside diameter, as illustrated in Figure 11.11, held at 3 m from the enclosure with a water pressure equal lo a head of nearly 3 m of water (— 30 kN/iiF), enough to give a delivery rate of 12.5 litres/min. The duration of Ihe lest will be determined at 1 min/m" of the surface area under test, subject lo a minimum of 3 minuies. 

Figure 11.11 Standard test nozzle for hose tests...

For a uniform spray on the entire test surface more nozzles may be employed. Normally, surfaces of up to a width of 3 m may be tested at a time. For larger widths the test may be conducted in two steps. Normally, only one vertical surface is tested at a time. Besides the vertical sections, the test will also be conducted on ... 

It is the energy in the liquid rec]uired to overcome the friction los.ses from the suction nozzle to the eye of the impeller without causing vaporization. It is a characteristic of the pump and is indicated on the pump s curve. It varies by design, size, and the operating conditions. It is determined by a lift test, producing a negative pressure in inches of mercury and converted into feet of required NPSH. 

ASMEflow nozzle. These nozzles provide for accurate measurements. Their use is limited because they are not easily placed in a process plant however, they are excellent for shop tests. Venturi meters and nozzles can handle about 60% more flow than orifice plates with varied pressure losses. 

Figure 20-3. Flow nozzle for subcritical flow. (Power Test Code 10, Compressors and Exhausters, American Society of Mechanical Engineers, 1965.)...

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