Dense Gas Flow in Minimum Length Nozzles

1995 ◽  
Vol 117 (2) ◽  
pp. 270-276 ◽  
Author(s):  
A. C. Aldo ◽  
B. M. Argrow
Keyword(s):  
Gas Flow ◽  
Van Der Waals ◽  
Axisymmetric Flow ◽  
Supersonic Nozzle ◽  
Wind Tunnels ◽  
Minimum Length ◽  
Nozzle Design ◽  
Dense Gas ◽  
Dense Gases ◽  
Real Gas Effects

Recently, dense gases have been investigated for many engineering applications such as for turbomachinery and wind tunnels. Supersonic nozzle design can be complicated by nonclassical dense-gas behavior in the transonic flow regime. In this paper, a method of characteristics (MOC) is developed for two-dimensional (planar) and axisymmetric flow of a van der Waals gas. A minimum length nozzle design code is developed that employs the MOC procedure to generate an inviscid wall contour. The van der Waals results are compared to perfect gas results to show the real-gas effects on the flow properties and inviscid wall contours.

Analysis of the Impact of Specific Heat Ratio on Two-Dimensional Low Maher Number Nozzle Design

2014 ◽  
Vol 590 ◽  
pp. 546-550
Author(s):  
Zhi Qiang Fan ◽  
Hai Bo Yang ◽  
Fei Zhao ◽  
Rong Zhu ◽  
Dong Bai Sun
Keyword(s):  
Specific Heat ◽  
Supersonic Nozzle ◽  
Two Dimensional ◽  
Nozzle Design ◽  
Scheme Design ◽  
Specific Heat Ratio ◽  
Nozzle Contour ◽  
Ratio Change ◽  
Change Impact ◽  
The Impact

The practical requirements of the project the nozzle entrance temperature is high, the gas specific heat ratio varies greatly, so it must consider the specific heat ratio change impact on two-dimensional nozzle contour design. Divided into consideration specific heat ratio change and not consider two kinds of scheme design of 1.4Ma nozzle profile and build the model using the arc line method, numerical simulation is carried out through the CFD software Fluent, analysis of two kinds of design scheme comparison. The results show that, in the supersonic nozzle at low Maher numbers, two schemes of nozzle design profile similarity, parameters change little flow tube, export the Maher number and the flow quality can meet the design requirements, proof of specific heat ratio has little effect on the design results in the design of the nozzle under the condition of low Maher number.

Behavior of Radial Incompressible Flow in Pneumatic Dimensional Control Systems

2003 ◽  
Vol 125 (5) ◽  
pp. 843-850 ◽  
Author(s):  
G. Roy ◽  
D. Vo-Ngoc ◽  
D. N. Nguyen ◽  
P. Florent
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Pressure Gauge ◽  
Axisymmetric Flow ◽  
Low Pressure ◽  
Industrial Applications ◽  
Nozzle Geometry ◽  
Machined Surface ◽  
Flow Area ◽  
Simpler Algorithm

The application of pneumatic metrology to control dimensional accuracy on machined parts is based on the measurement of gas flow resistance through a restricted section formed by a jet orifice placed at a small distance away from a machined surface. The backpressure, which is sensed and indicated by a pressure gauge, is calibrated to measure dimensional variations. It has been found that in some typical industrial applications, the nozzles are subject to fouling, e.g., dirt and oil deposits accumulate on their frontal areas, thus requiring more frequent calibration of the apparatus for reliable service. In this paper, a numerical and experimental analysis of the flow behavior in the region between an injection nozzle and a flat surface is presented. The analysis is based on the steady-state axisymmetric flow of an incompressible fluid. The governing equations, coupled with the appropriate boundary conditions, are solved using the SIMPLER algorithm. Results have shown that for the standard nozzle geometry used in industrial applications, an annular low-pressure separated flow area was found to exist near the frontal surface of the nozzle. The existence of this area is believed to be the cause of the nozzle fouling problem. A study of various alternate nozzle geometries has shown that this low-pressure recirculation area can be eliminated quite readily. Well-designed chamfered, rounded, and reduced frontal area nozzles have all reduced or eliminated the separated recirculation flow area. It has been noted, however, that rounded nozzles may adversely cause a reduction in apparatus sensitivity.

Steady small-disturbance transonic dense gas flow past two-dimensional compression/expansion ramps

2018 ◽  
Vol 848 ◽  
pp. 756-787 ◽  
Author(s):  
A. Kluwick ◽  
E. A. Cox
Keyword(s):  
Gas Dynamics ◽  
Gas Flow ◽  
External Forcing ◽  
Two Dimensional ◽  
Small Disturbance ◽  
Dense Gas ◽  
Dimensional Flow ◽  
Flow Past ◽  
Two Dimensional Flow ◽  
Dimensional Parameters

The behaviour of steady transonic dense gas flow is essentially governed by two non-dimensional parameters characterising the magnitude and sign of the fundamental derivative of gas dynamics ($\unicode[STIX]{x1D6E4}$) and its derivative with respect to the density at constant entropy ($\unicode[STIX]{x1D6EC}$) in the small-disturbance limit. The resulting response to external forcing is surprisingly rich and studied in detail for the canonical problem of two-dimensional flow past compression/expansion ramps.

Effect of Slip Velocity and Heat Transfer on the Condensed Phase Momentum Flux of Supersonic Nozzle Flows

1999 ◽  
Vol 122 (1) ◽  
pp. 14-19 ◽  
Author(s):  
S. A. Sherif ◽  
W. E. Lear ◽  
N. S. Winowich
Keyword(s):  
Heat Transfer ◽  
Momentum Flux ◽  
Slip Velocity ◽  
Figure Of Merit ◽  
Supersonic Nozzle ◽  
Nozzle Design ◽  
Gaseous Nitrogen ◽  
Liquid Phases ◽  
Nozzle Flows ◽  
Phase Momentum

One of the methods used for industrial cleansing applications employs a mixture of gaseous nitrogen and liquid water injected upstream of a converging-diverging nozzle located at the end of a straight wand assembly. The idea is to get the mixture to impact the surface at the maximum momentum flux possible in order to maximize the cleansing effectiveness. This paper presents an analysis geared towards this application in which the effects of slip and heat transfer between the gas and liquid phases are present. The model describes the liquid momentum flux (considered a figure of merit for cleansing) under a host of design conditions. While it is recognized that the emulsification mechanism responsible for cleansing is far more complicated than simply being solely dependent on the liquid momentum flux, the analysis presented here should prove useful in providing sufficiently accurate results for nozzle design purposes. [S0098-2202(00)01801-0]

Large Eddy Simulation of dense gas flow around a turbine cascade

2019 ◽  
Author(s):  
Jean-Christophe Hoarau ◽  
Paola Cinnella ◽  
Xavier Gloerfelt
Keyword(s):  
Large Eddy Simulation ◽  
Gas Flow ◽  
Dense Gas ◽  
Turbine Cascade ◽  
Eddy Simulation ◽  
Large Eddy

Supercooling in hypersonic nitrogen wind tunnels

1994 ◽  
Vol 269 ◽  
pp. 283-299 ◽  
Author(s):  
Wayland C. Griffith ◽  
William J. Yanta ◽  
William C. Ragsdale
Keyword(s):  
Vibrational Energy ◽  
Ideal Gas ◽  
Wind Tunnels ◽  
Pure Nitrogen ◽  
Real Gas ◽  
Absolute Limit ◽  
Real Gas Effects ◽  
Supercooled Region ◽  
The Ideal

Recent experimental observation of supercooling in large hypersonic wind tunnels using pure nitrogen identified a broad range of non-equilibrium metastable vapour states of the flow in the test cell. To investigate this phenomenon a number of real-gas effects are analysed and compared with predictions made using the ideal-gas equation of state and equilibrium thermodynamics. The observed limit on the extent of supercooling is found to be at 60% of the temperature difference from the sublimation line to Gibbs’ absolute limit on phase stability. The mass fraction then condensing is calculated to be 12–14%. Included in the study are virial effects, quantization of rotational and vibrational energy, and the possible role of vibrational relaxation and freezing in supercooling. Results suggest that use of the supercooled region to enlarge the Mach–Reynolds number test envelope may be practical. Data from model tests in supercooled flows support this possibility.

Fabrication of Apatite/Titanium Functionally Graded Coating Using Supersonic Free-Jet PVD

2009 ◽  
Vol 631-632 ◽  
pp. 187-192
Author(s):  
Atsushi Yumoto ◽  
Takahisa Yamamoto ◽  
Ichiro Shiota ◽  
Naotake Niwa
Keyword(s):  
Composite Coating ◽  
Gas Flow ◽  
Supersonic Nozzle ◽  
In Vitro Study ◽  
Functionally Graded ◽  
Inert Gas ◽  
Coating Film ◽  
Evaporation Chamber ◽  
Free Jet

Hydroxyapatite (HAp) is very attractive in medical field. The objective of this study is to produce HAp/Ti composite coating with Supersonic Free-Jet PVD (SFJ-PVD). The SFJ-PVD is a technique to deposit nanoparticles with supersonic gas flow and to form a thick coating film. In a gas evaporation chamber, a source material is evaporated to form nanoparticles in an inert gas atmosphere. The nanoparticles are then carried to a substrate in a deposition chamber with an inert gas flow through a transfer pipe. The gas flow is generated by the pressure difference between the chambers and accelerated to the supersonic flow of 4.2 Mach through a specially designed supersonic nozzle. With SFJ-PVD, we obtain a uniform high-density HAp/Ti composite coating. XRD analysis reveals that the composite coating is composed of Ti and HAp. An in-vitro study was carried out to investigate the bioactivity of the HAp/Ti composite coating under simulated body fluid.

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