Experimental investigation of isolated Hypersonic Inlet

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Title of the contributed paper for NCWT04

A Satyanarayana

,

Ch Srikanth

,

J Chandrasekhar

,

S V Ramana

+

Defence Research and Development Laboratory, Hyderabad, India.

(corresponding_author@efgh.ijk)

ABSTRACT

A 1:8 scale model of isolated inlet (air-intake) of Hypersonic Technology Demonstrator Vehicle

(HSTDV) was tested at Mach 3.6 in 340 mm diameter enclosed free jet Supersonic Blow down Wind tunnel at

DRDL, Hyderabad. The test Reynolds number is 65 million per meter and stagnation temperature is 300K.

Tests were conducted using replaceable cowls of different lengths at different cowl hinge line locations to study the starting characteristics of the intake. To simulate the flight condition, the cowl is initially kept in closed position and then opened to the desired angle using a hydraulic actuator. Experiment consists of internal surface pressure measurement and flow visualization by shadowgraphs. Results indicate that shifting of cowl hinge line rearward improved the starting characteristics significantly.

Key Words : Contraction ratio, cowl hinge line location, started and un-started intake

CR

P

M

1.

ABBREVIATIONS

INTRODUCTION

= Contraction Ratio, (ratio of cross-sectional

areas of throat and intake entry)

= Pressure

= Mach number

L e

NOMENCLATURE

= Horizontal distance between leading edge

of bottom wall and leading edge of cowl

L h

= Horizontal distance between leading edge

of bottom wall and cowl hinge line

 cowl

= Angle between cowl bottom surface and

free stream, degrees

Hypersonic Technology Demonstrator Vehicle

(HSTDV) is being developed by DRDL to prove the high-end technologies such as scramjet propulsion, high temperature materials and high temperature aerothermodynamics at hypersonic speeds.

3.

METHODOLOGY

A 1:8 scale model is chosen from the consideration of blockage to the flow. Blockage area of the model and its support strut is about 8% of test section area. The model is of modular construction and has a box type structure with constant width of

6.4h, where ‘h’ is the isolator height. The model consists of four sections: flat plate with side fences, contraction, constant area and divergent portion.

A number of static pressure ports of 1 mm diameter were located along the centre line of the bottom wall, top wall and side wall. Polyurethane tubes from each of the pressure ports were connected to scannivalve located inside the tunnel plenum chamber and a few were connected in parallel to the pressure transducers.

In Eqn. (1), …

 r

2

0

F ( r ,

) dr d

 

[

 r

2

/ ( 2

0

)]

(1)

2.

LITERATURE REVIEW

Referencing a literature use number citations on the line, in square brackets, multiple references are each numbered with separate brackets, [1] [2]. Do not use “Ref.” or “reference” except at the beginning of a sentence: “Reference [3] shows ....”

__________________________________________

Scientists, Aero Test Facilities Division, Directorate of Aerodynamics

+

Technical Officer, Aero Test Facilities Division,

Directorate of Aerodynamics

© A Satyanarayana, Ch Srikanth, J Chandrasekhar and S V Ramana

4.

RESULTS AND DISCUSSION

4.1

Started and unstarted intake

Surface pressure distribution over the bottom wall of the intake is shown in Fig. 4a for intake with cowl 1. The pressure data of the intake with cowl 1 for cowl opening angle of 8º (corresponding CR =

0.441) shows that the pressure distribution up to cowl entry is same and is equivalent to free stream static pressure.

4.2

Effect of cowl hinge line location on the intake flow field

Surface pressure distribution on the bottom wall of the intake with cowl 2 is also shown in Fig. 4a for cowl opening angle of 13.75º. For cowl 1 and cowl 2,

2 Paper Title the leading edge location of cowls is same for both the intakes (11h).

4.3

Summary of the test results

The summary of the test results is given in

Table II. From the table, it is observed that shifting of the hinge line location rearward and using longer cowl improves the pressure recovery and the mass flow through the intake.

5.

CONCLUSION

A 1:8 scale air-intake model of Hypersonic

Technology Demonstrator Vehicle was tested in

340mm diameter enclosed free jet supersonic wind tunnel at Mach 3.6.

Acknowledgment

The authors express thanks

Shri. H. Govindarajan, Technology Director, DOAD and HSTDV Project Team for useful discussions and suggestions. The authors are also thankful to ATF team for providing all the necessary support during the test program.

REFERENCES

[1] A. Satyanarayana, et al “Experimental

Investigation of Isolated Hypersonic Inlet”,

Proceedings of SAROD, Dec 2005.

[2] Ch. Srikanth, et al “Starting characteristics of isolated air-intake of a Hypersonic Technology

Demonstrator Vehicle” p-126, NCAE 2008.

[3]

E.L. Goldsmith, J. Seddon, “Practical Intake

Aerodynamic Design”, Blackwell scientific publications, 1993.

Table I: Cowl details

Config. Cowl 1 Cowl 2 Cowl 3

Lh 16.7h 19 h 19 h

Le 11 h 11 h 12.1 h

Table 2: Summary of Test Results

Cowl Configuration Cowl 1 Cowl 2 Cowl 3

Hinge location, L h

16.7 h 19 h 19h

Cowl length 5.7 h 8h 6.9h

Pressure recovery 7 10 8

Fig. 3a: Effect of hinge line location on bottom

Fig. 3b: Effect of hinge line location on side wall pressure distribution

1. Dr. A. Satyanarayana is postgraduate in Aero from

IIT Madras and working in the field of wind tunnel testing in DRDL as Scientist-F.

Brief profile (5-6 Lines) with photograph of author (Maximum of three).

Fig. 1: Configuration of Hypersonic Technology

Demonstrator Vehicle

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