Analytical and Numerical Design of a High Performance Double–Throated Supersonic Blowdown Windtunnel

2016 ◽  
Author(s):  
Philipp Epple ◽  
Michael Steppert ◽  
Michael Steber
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Design Process ◽  
Test Section ◽  
Method Of Characteristics ◽  
Design Procedure ◽  
Optimum Shape ◽  
Supersonic Wind Tunnel ◽  
Convergent Nozzle ◽  
The Method Of Characteristics

In this publication the focus lies on the design process of the full supersonic double throated wind tunnel. Starting with the fundamental equations of gas dynamics in combination with an analytical model of the pressure reservoir, the area of the throat at the nozzle and the runtime of the blowdown wind tunnel were computed. Based on these results, the shape of a shock free nozzle was calculated by the method of characteristics. For this purpose, a nozzle design program was developed using Python. In order to validate the results of the method of characteristics program, these results were compared with the area-Mach number relation, which is the exact analytical solution of the isentropic flow through supersonic nozzles. The convergent part of the nozzle, which initially accelerates the flow to sonic speed, cannot be calculated by the method of characteristics, since it applies to supersonic flows only. Hence the subsonic convergent section of the nozzle was designed directly with 2D CFD using CD Adapco Star-CCM+ v. 10.06. A parametric model of the convergent nozzle section was used to find the optimum nozzle shape, i.e. a nozzle which results in a maximum mass flow rate in order to have an undisturbed flow field and Mach number in the following test section. In order to decelerate the flow again from supersonic to subsonic flow after the test section and minimize the total pressure losses, an oblique shock diffuser was used [1]. As for the convergent subsonic nozzle, the optimum shape of a diffusor was found by 2D CFD analysis. Putting all these elements together, i.e. nozzle, test section and diffuser the optimum supersonic wind tunnel shape was found. Finally, a full 3D simulation of the supersonic wind tunnel was performed in order to validate the complete design procedure and computations and also to include the viscous effect of the side walls. These results and the whole design process are presented and analyzed in the paper.

scholarly journals Design of Minimum Length Supersonic Nozzle using the Method of Characteristics

2019 ◽  
Vol 9 (2) ◽  
pp. 1370-1374
Keyword(s):  
Mach Number ◽  
Combustion Chamber ◽  
Method Of Characteristics ◽  
Supersonic Nozzle ◽  
Minimum Length ◽  
Convergent Nozzle ◽  
The Method Of Characteristics ◽  
Inlet Conditions ◽  
The Given ◽  
Nozzle Inlet

The work focuses upon design of minimum length supersonic nozzle, using the method of characteristics, for the given combustion chamber conditions, which are going to serve as nozzle inlet conditions. It is assumed that the flow has somehow been accelerated to the sonic value through a suitable convergent nozzle and from that point; the divergent portion of the nozzle is to be designed using the method of characteristics. The optimum exit area and hence, the Mach number are predicted and this Mach number is the value for which the nozzle has to be designed. The results obtained are validated with the results obtained by validation in ANSYS and based on the observation, followed by a discussion on the optimisation of results.

scholarly journals Nozzle flows found by the hodograph method. II

1960 ◽  
Vol 1 (3) ◽  
pp. 357-367 ◽  
Author(s):  
T. M. Cherry
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Test Section ◽  
Wind Tunnels ◽  
Perfect Gas ◽  
Supersonic Wind Tunnel ◽  
Hodograph Method ◽  
Sonic Nozzle ◽  
Polytropic Equation ◽  
Nozzle Flows

This is a sequel to a recent paper [1] on the construction by the hodograph method of trans-sonic nozzle-flows of a perfect gas. At the end of that paper it was shown how we can obtain regular flows that are ultimately uniform (as required in the test section of a supersonic wind tunnel), and the object now is to give some quantitative examples of such flows. The gas is supposed to have the polytropic equation of state Pρ−γ = constant, and the calculations have been made for the case γ = 1.4, with the Mach number M = 2.25 at the test section. The results, which are exhibited graphically, are indicative of what may be expected for other supersonic values of M, and it is hoped that they may be significant for the design of wind tunnels.

Design of a continuous portable indraft supersonic wind tunnel

2020 ◽  
pp. 030641902090734
Author(s):  
Monty Bruckman II ◽  
Lance W Traub
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Sound Level ◽  
Wind Tunnels ◽  
Supersonic Wind Tunnel ◽  
Blow Down ◽  
Hands On ◽  
Compressible Fluid Flow ◽  
Aeronautical Engineering ◽  
Design And Manufacture

Programs in mechanical and aeronautical engineering commonly include courses in compressible fluid flow. As such, learning can be greatly enhanced if theory is taught in conjunction with hands on experimentation. While supersonic wind tunnels are not uncommon at many universities, such facilities are generally of the blow down configuration. Consequently, run time is very short and ear protection is required during operation, potentially hindering instruction. Furthermore, blow down configurations are typically expensive and large. This article presents the design and manufacture of a continuous, indraft, miniature supersonic wind tunnel. The tunnel was designed for a nominal test section Mach number of 2; validation indicated a Mach number of 1.96 was achieved. Vacuum was provided by a regenerative blower. The facility is portable and quiet; measurements indicated that the sound level around the tunnel when operational was less than 81 dB (compared to 119dB generated by the department’s blow down supersonic wind tunnel).

The Effect of Pulsed Injection on Supersonic Shear Layer Mixing in a Scramjet Combustor

2018 ◽  
Vol 35 (3) ◽  
pp. 203-215
Author(s):  
Leslie Smith ◽  
Saeed Farokhi
Keyword(s):  
Wind Tunnel ◽  
Shear Layer ◽  
Test Section ◽  
Pulse Width ◽  
Static Pressure ◽  
Experimental Studies ◽  
Lower Wall ◽  
Supersonic Wind Tunnel ◽  
Scramjet Combustor ◽  
Secondary Injection

Abstract A novel injector has been designed and cold flow injection tests were performed in a modified supersonic wind tunnel. To complement these experimental studies three dimensional STAR-CCM+CFD simulations were developed. The pulse width may be varied, with options of injecting gas for 33 %, 50 % and 66 % of the injection period. The scramjet combustor environment is simulated in a supersonic wind tunnel through a backward facing step for secondary injection purposes and a 157.5 cm (62-inch) long test section. The gas in secondary injection is carbon dioxide and the primary flow is air. The simulations show a coupled interaction between the forcing from injection and the shear layer. Steady state static pressure measurements on the lower wall of the wind tunnel test section agree well with the simulated static pressure along the lower wall. The pulse width strongly impacts shear layer reattachment on the lower wall and varies between 2.4 and 4.3 step heights. Reduction in duty cycle from 66 % to 33 % at 1 kHz caused ~30 % reduction in the shear layer reattachments distance, which points to large scale mixing enhancement.

Design, Fabrication, and Realization of a Supersonic Wind Tunnel for Educational Purposes

2009 ◽  
Vol 37 (4) ◽  
pp. 286-303 ◽  
Author(s):  
Mohammed K. Ibrahim ◽  
A. F. Abohelwa ◽  
Galal B. Salem
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Compressible Flows ◽  
Basic Education ◽  
Design Parameters ◽  
High Tech ◽  
Design Phase ◽  
Supersonic Wind Tunnel ◽  
Design Error ◽  
Standard Textbook

The supersonic wind tunnel is an indispensable facility for basic education in any course that covers compressible flows and one of the main pillars of any aerodynamic laboratory. The introduction of a supersonic wind tunnel at the aerodynamics laboratory of the Aerospace Engineering Department at Cairo University had often been postponed and was hindered by a lack of funds for the purchase of foreign equipment and expertise. Thoughts therefore turned to building such facility instead of buying it, substituting high-tech and complex foreign equipment for locally produced equipment, and ‘thinking out of the box’ to make the most use of available resources, even when this led to some unconventional applications. An extensive scheme for the design, fabrication, and realization of a multi-Mach number ( M = 1.5, 2, and 2.5) supersonic wind tunnel for laboratory experiments is proposed in this paper. The proposed scheme is simple, detailed and multi-level; it starts by utilizing one-dimensional isentropic flow theory for the conceptual design phase and makes full use of computational fluid dynamics at the detailed design phase. This ensured that we had a working design before we embarked on the manufacture of any components, which would have been costly to modify had there been any design error. A parametric study has been carried out for a number of design parameters, using numerical simulations. After the design and fabrication, a number of successful standard textbook experiments, for Mach number 2, were carried out as validation for the proposed scheme. The results showed good agreement with the theoretical predictions.

Investigation of Transient Shock Wave in Supersonic Wind Tunnel

2012 ◽  
Vol 232 ◽  
pp. 228-233
Author(s):  
Behnam Ghadimi ◽  
Mojtaba Dehghan Manshadi ◽  
Mehrdad Bazazzadeh
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Wind Tunnel ◽  
Pressure Ratio ◽  
Wind Tunnels ◽  
Supersonic Wind Tunnel ◽  
Blow Down ◽  
Fortran Code ◽  
Nozzle Contour ◽  
Fluent Software

Wind tunnels are the experimental apparatuses which provide an airstream flowing under controlled conditions so that interesting items in aerospace engineering such as pressure and velocity can be tested. In this work, Shock wave passes through the intermittent blow-down wind tunnel at Mach=2,3,4 has been investigated. The shape of the nozzle contour for a given Mach number was determined using the method of characteristics. For this purpose MATLAB code was developed and this code was verified with Osher’s and AUSM methods, FORTRAN code and FLUENT software was used for these two methods, respectively. Dimensions of different parts of wind tunnel are determined and minimum pressure ratio for the starting condition has been founded using FLUENT software. Good agreement was considered compared with the data from eleven tunnels over their range of Mach number.

The Ludwieg Pressure-Tube Supersonic Wind Tunnel

1963 ◽  
Vol 14 (2) ◽  
pp. 143-157 ◽  
Author(s):  
A. J. Cable ◽  
R. N. Cox
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Nozzle Exit ◽  
High Speed ◽  
Layer Growth ◽  
Stagnation Pressure ◽  
Pressure Tube ◽  
Rarefaction Waves ◽  
Supersonic Wind Tunnel ◽  
Blow Down

SummaryA description is given of a supersonic pressure-tube wind tunnel which has been constructed at A.R.D.E. This is a blow-down tunnel which uses as a reservoir a long tube filled with gas under pressure. A quasi-steady supersonic flow is achieved by expanding in a convergent-divergent nozzle the subsonic flow behind rarefaction waves which propagate down the tube when a diaphragm at the nozzle exit is burst. The theory of the operation of the tunnel is given and calculations are made of the boundary-layer growth along the tube. Pressure-time records were obtained in the tube, and a high speed camera was used to obtain pictures of the flow round a model. Measurements also included a pitot-tube traverse of the nozzle exit, and the Mach number distribution was determined from the ratio of the pitot to the stagnation pressure. Tests showed that, as predicted, a constant stagnation pressure was obtained ahead of the nozzle, and it is considered that a tunnel of this type would be a cheap and simple way of obtaining an intermittent tunnel with adequate running time for many types of test, and capable of operating at a Reynolds number of more than 107 per inch at a Mach number of about 3·5.

The Study of Design and Installation Process for Supersonic Nozzle

2012 ◽  
Vol 569 ◽  
pp. 500-503
Author(s):  
Lian Sheng Wu ◽  
Guang Li Li ◽  
Qi Fu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Test Section ◽  
Supersonic Nozzle ◽  
Simulation Method ◽  
Supersonic Wind Tunnel ◽  
Numerical Simulation Method ◽  
Field Quality ◽  
The Impact

A practical optimal design method of supersonic nozzle is proposed for a supersonic wind tunnel’s design. Design a set of nozzle wall lines with the same nozzle length and different Mach numbers 1.5, 2.0, 2.5. Use numerical simulation method for the verify and analysis of the designed nozzle. Mainly study the impact of the installation gradient between nozzle and test section on flow field quality. This wind tunnel is the subsonic, transonic and supersonic wind tunnel and its test section cross is 0.2 m × 0.2 m .The impact on flow field quality of the test section was studied quantitatively by using the numerical simulation method. The installation gradient index was given. It has some practical value to the construction of supersonic wind tunnel. At present, this study has been applied in construction of the wind tunnel. The gradient of the test section import shall not be greater than 0.5 mm.

Experimental Study of Mixed Compression Air-Intake for Hypersonic Airbreathing Engines

1992 ◽  
Author(s):  
Kimio Sakata ◽  
Ryoji Yanagi ◽  
Akira Murakami ◽  
Shigemi Shindo ◽  
Shinji Honami ◽  
...  
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Wind Tunnel ◽  
Wave System ◽  
Joint Research ◽  
Supersonic Wind Tunnel ◽  
Isentropic Compression ◽  
Boundary Layer Interaction ◽  
Air Intake ◽  
Shock System

Supersonic air-intake for Mach number higher than 2.5 is being investigated with experimental, analytical and computational methods. The study is performed in a part of the joint research program led by National Aerospace Laboratory (NAL) on the hypersonic airbreathing turbo-engines with subsonic ram combustion. The wind tunnel models are designed in two-dimensional mixed compression type with multi-shock system and tested in NAL’s Mach 4 supersonic wind tunnel. Pressure measurements and flow visualization by schlieren method, oil-flow and vapor screen techniques are being done. Here, the test results of Mach 4 and Mach 5 models are discussed. The Mach 4 model is fixed geometry with 5-shock system and the Mach 5 one is variable geometry with 6-shock and an isentropic compression surface. An expansion fore-plate was installed at the Mach 5 model inlet to accelerate the air-speed at the entry. The bleed systems at throat, ramp and cowl are adopted and evaluated in terms of pressure recovery and stability. Importance of establishment of the internal shock wave system, reduction of upstream Mach number of terminal shock wave and suppression of flow separation at diffusers are found. It is also found that ramp bleed is effective to confirm intake start and to minimize shock/boundary layer interaction.

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