Experimental investigation of the characteristics of small-sized nozzles

Butenko, V.A.; Rylov, Yu. P.; Chikov, V. P.

doi:10.1007/bf01026418

Cited by 7 publications

(6 citation statements)

References 2 publications

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“…The reduction of cross sectional area for a subsonic flow produces a favourable pressure gradient and an acceleration of the fluid [55], avoiding wall separation; as a result, the efficiency of the nozzles is usually very high, often exceeding 96 % [56,57]. Anyway, for small size nozzles, in which the throat width is lower than 3 mm, the boundary layer might occupy a significant portion of the cross sectional area [58], generating increased viscous losses. In these cases, the flow is laminar (Re<10 5 ) and the total pressure losses decrease with Reynolds number increase [58].…”

Section: Stator Flow Modelmentioning

confidence: 99%

Design and optimization of a Tesla turbine for ORC applications

et al. 2018

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Section: Stator Flow Modelmentioning

confidence: 99%

Design and optimization of a Tesla turbine for ORC applications

et al. 2018

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“…2. The losses in total pressure in small nozzles decrease as the Reynolds number increases [30]. Thus, the best performance would be reached when the flow velocity through the nozzle reached its maximum value.…”

Section: Choking Upstream Of the Nozzlementioning

confidence: 99%

“…This is because as the inlet pressure increases, the Mach number of the flow in the nozzle increases. This causes the boundary layers to become thinner which reduces the viscous losses in the nozzle [30,31]. After the flow is choked, the static pressure of the jet at the nozzle exit increases with increasing nozzle inlet total pressure, which results in an increased fluid density in the nozzle.…”

Section: Efficacy Of Various Nozzle-inlet Assembliesmentioning

confidence: 99%

“…For small-sized nozzles with throat widths of less than 3 mm, the boundary layer can occupy a significant portion of the nozzle area [30]. Flows in these nozzles are characterized by small Reynolds numbers (Re < 10 5 ) and are laminar [30]. The relative thickness of the boundary layer can result in reduced nozzle performance because of increased viscous losses [31].…”

Section: Introductionmentioning

confidence: 99%

“…The relative thickness of the boundary layer can result in reduced nozzle performance because of increased viscous losses [31]. In nozzles of this kind it is found that total pressure losses decrease as the Reynolds number of the flow increases [30], since the thickness of the boundary layer decreases with increasing Reynolds number.…”

Section: Introductionmentioning

confidence: 99%

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Experiment and analysis for an improved design of the inlet and nozzle in Tesla disc turbines

Guha

Smiley

2010

Proceedings of the Institution of Mechanical Engineers, Part A:

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In this article, the performance of the inlet to a Tesla disc turbine has been studied. The losses in the inlet and nozzle are known to be a major reason why the overall efficiency of disc turbines is not high. A new nozzle utilizing a plenum chamber inlet has been designed and tested here. Experiments have demonstrated less than 1 per cent loss in total pressure in the new design compared to losses in the range 13–34 per cent for the original nozzle and inlet. Other than the dramatic improvement in loss reduction, the new plenum-integrated nozzle achieves a considerable enhancement in the uniformity of the jet. This has been demonstrated here both by experimental traverses of Pitot tubes as well as computational fluid dynamics studies. The greater uniformity of the jet means that a single Pitot measurement approximately positioned at the centre of the jet would record a value close to the true centre-line total pressure, and that calculations based on centre-line values of total pressure would give, to a good accuracy, the average loss coefficient of the nozzle—inlet assembly. The uniformity of the jet also means that all disc passages would receive uniform inlet conditions; this should improve the performance of the rotor thereby further enhancing the overall efficiency of the Tesla turbine.

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