Effect of Nozzle Shape on Amplitude of Well Acoustic Emitter Generation

2018 ◽  
Vol 64 (4) ◽  
pp. 492-502 ◽  
Author(s):  
A. A. Abdrashitov ◽  
E. A. Marfin ◽  
D. V. Chachkov ◽  
V. M. Chefanov
Keyword(s):  
Acoustic Emitter ◽  
Nozzle Shape

scholarly journals Sensitivity of Supersonic ORC Turbine Injector Designs to Fluctuating Operating Conditions

2015 ◽  
Author(s):  
Elio A. Bufi ◽  
Paola Cinnella ◽  
Xavier Merle
Keyword(s):  
Method Of Characteristics ◽  
Organic Rankine Cycle ◽  
Design Procedure ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Real Gas ◽  
Real Gas Effects ◽  
Nozzle Shape ◽  
Turbine Design ◽  
The Impact

The design of an efficient organic rankine cycle (ORC) expander needs to take properly into account strong real gas effects that may occur in given ranges of operating conditions, which can also be highly variable. In this work, we first design ORC turbine geometries by means of a fast 2-D design procedure based on the method of characteristics (MOC) for supersonic nozzles characterized by strong real gas effects. Thanks to a geometric post-processing procedure, the resulting nozzle shape is then adapted to generate an axial ORC blade vane geometry. Subsequently, the impact of uncertain operating conditions on turbine design is investigated by coupling the MOC algorithm with a Probabilistic Collocation Method (PCM) algorithm. Besides, the injector geometry generated at nominal operating conditions is simulated by means of an in-house CFD solver. The code is coupled to the PCM algorithm and a performance sensitivity analysis, in terms of adiabatic efficiency and power output, to variations of the operating conditions is carried out.

Vector Control of Synthetic Jets Using an Asymmetric Slot

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Ryota Kobayashi ◽  
Koichi Nishibe ◽  
Yusuke Watabe ◽  
Kotaro Sato ◽  
Kazuhiko Yokota
Keyword(s):  
Cross Section ◽  
Rigid Wall ◽  
Synthetic Jets ◽  
Dimensionless Frequency ◽  
Fundamental Study ◽  
Recirculation Flow ◽  
Projection Length ◽  
Wire Method ◽  
Nozzle Shape ◽  
Flow Visualizations

This paper presents a fundamental study on jet vectoring control by adjusting the dimensionless frequency of synthetic jets over time without changing the injection nozzle shape in actuators. This work involves the introduction of asymmetric slots with various sharp projection lengths in free synthetic jets for various actuator frequencies. The influences of the dimensionless parameters, sharp projection length C, and actuator frequency f* on the behavior of free synthetic jets are experimentally investigated under the same slot width b and Reynolds number Re = 990, and numerical simulations are performed to supplement these experiments. Furthermore, the behavior of synthetic jets is compared with that of continuous jets. The measurements of the velocities for both jet types are performed for the flow visualizations to observe the jet behaviors obtained using the smoke-wire method. The typical flow patterns and the time-averaged velocity distributions of the synthetic jets for various sharp projection lengths and dimensionless frequencies are demonstrated through the experiment. The influence of the dimensionless frequency on the stagnation point near a rigid wall when the inclined synthetic jets form a recirculation flow is also investigated. Furthermore, the degree of the bend of the jets is evaluated based on the change in the jet center's position at a reference downstream cross section. The results show that the jet direction of the synthetic jets induced by the asymmetric slots is related to both the dimensionless sharp projection length and the dimensionless frequency.

scholarly journals Nozzle Shape Guided Filler Orientation in 3D Printed Photo-curable Nanocomposites

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Taeil Kim ◽  
Ramita Trangkanukulkij ◽  
Woo Soo Kim
Keyword(s):  
3D Printed ◽  
Nozzle Shape

RECOMPRESSION PHENOMENA IN STEAM NOZZLES: PART I

1941 ◽  
Vol 19a (5) ◽  
pp. 67-85 ◽  
Author(s):  
Charles Alexander Robb
Keyword(s):  
Cross Section ◽  
Inlet Pressure ◽  
Flowing Fluid ◽  
Vena Contracta ◽  
Venturi Effect ◽  
Change Of State ◽  
Expansion Curve ◽  
Nozzle Shape ◽  
The Difference ◽  
Load Conditions

The purpose of the investigation was to find when and how recompression occurs in the flow of steam through a nozzle, its causes and effects, how the results can be predicted, and what losses are caused by these phenomena. Four types of recompression were observed: equilibrium, latent, vena contracta, and shock recompression.It is shown that steam in flowing through a nozzle of varying cross-section responds to the changes of area within certain limits and recompression phenomena may be expected. The Venturi effect has been observed in single nozzles, and in both parts of a composite nozzle.The behaviour of steam in equilibrium recompression in convergent-divergent nozzles can be predicted by means of an equation from which a valuers obtained for the pressure pr at which overexpansion ends and an increase in pressure begins; the pressure pr depends on the inlet pressure to the nozzle and on the difference in pressure at inlet and outlet.The recompression due to the contraction of the section can be controlled and avoided by suitable provision in the design. The compression following a change of state of a flowing fluid can be controlled by adjusting the rate of expansion of the fluid in specified pressure ranges. Novel evidence of latent recompression is found in a break or notch in the pressure expansion curve plotted from search tube observations.The experiments were carried out at inlet pressures within the range at which turbine-condition curves may cross the saturation line between the superheat and wet regions on the Mollier diagram, and the effects of recompression to be expected under varying load conditions can be interpreted for particular nozzle designs.Comparative studies of the effect of the nozzle shape on recompression phenomena and the losses resulting therefrom have indicated that the conditions for favourable efficiency require a larger inlet radius at the throat and a length shorter than the lengths commonly found in practice.

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