Prediction of total pressure characteristics in the settling chamber of a supersonic blowdown wind tunnel

Bhoi,; Suryanarayana, GK

doi:10.1017/s0001924000006199

Cited by 9 publications

(3 citation statements)

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“…Smanjenje prelaznih opterećenja može da se postigne smanjenjem minimalnog početnog pritiska ispitivanja, korišćenjem drugog grla ili ejektora u difuzoru aerotunela, modifikaciјama u procedurama uspostavljanja i zaustavljanja struјanja u aerotunelu [4] ili kontinualnom promenom geometriјe mlaznika (rešenje koje nikada niјe bilo primenjeno u aerotunelima prekidnog deјstva usled očekivane i opasne tendenciјe rasta pritiska tokom tranziciјe [5]).…”

Section: Definisanje Problemaunclassified

A technique for reducing supersonic transient loads on internal wind tunnel balances

Vuković,

Damljanović

2024

Tehnika

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Design of slender supersonic missiles requires a comprehensive experimental support in the form of wind tunnel data for a wide range of flight parameters (angle of attack and Mach number). However, in supersonic wind tunnel testing, the problem exists of transient loads at the times of the starting and stopping of the supersonic flow. In the environments of pronounced transient loads, characteristic of blowdowin wind tunnels like the T-38 of the Military technical Institute in Belgrade, it is necessary to provide control of the use of internal wind tunnel balances in the permitted design load ranges. The presented technique is related to the definition and implementation of a methodology for reducing the transient loads on wind tunnel balances in supersonic wind tunnel tests. By limiting the clearance between the model and its tail support (sting) to a magnitude which permits normal tests, but results in model-support contact during the excessive loads, part of the loads is transferred to the support sting, relieving the balance. The technique improves control over the wind tunnel test process, improves measurement accuracy and prevents damage to sensitive instrumentation (wind tunnel balances).

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Section: Definisanje Problemaunclassified

A technique for reducing supersonic transient loads on internal wind tunnel balances

Vuković,

Damljanović

2024

Tehnika

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“…The controlling precisions of the total pressure and the Mach number are the final goals of the design and optimization for the pressure-regulating valve. 16…”

Section: Pneumatic and Structure Designsmentioning

confidence: 99%

Numerical evaluation on aerodynamic design of pressure-regulating valve in trisonic intermittent wind tunnel

Zhang

Xiao

Zhang

et al. 2021

Advances in Mechanical Engineering

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The pressure-regulating valve can realize the rapid adjustment and precise controlling of operating pressure and Mach number, to stabilize the flow field and avoid the test interference such as the air source loss or the unstable flow. This paper takes the design and optimization of pressure-regulating valve in trisonic intermittent wind tunnel as the research object to investigate its special pressure-regulating characteristic and performance in the wind tunnel. According to the requirement of the wind tunnel, the annular-gap type pressure-regulating valve is selected to match its wide adjustment range of operating parameter, high regulation accuracy, and low running resistance. The design and optimization of the pressure-regulating valve are carried out, including aerodynamic and structural design, analysis on pressure regulation characteristics, kinematics analysis, flow field analysis, vibration analysis, and structure optimization. The design and selection of some important components are carried out based on the pneumatic design and performance requirements. The pressure regulation characteristics of the pressure regulating valve are discussed and the affecting factors of the irregular flow are analyzed and evaluated by numerical simulation. The final structure of the pressure-regulating valve is determined and the test results perform well with prediction of characteristic curve.

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“…Another technique of reducing transient loads acting on the model has been attempted more recently, and it incorporates modifications of the wind tunnel start and unstart procedures. 4 As the transient loads typically increase with Mach number and stagnation pressure, the problem is alleviated by gradually increasing, when starting a wind tunnel, the supersonic Mach number and stagnation pressure of the flow in the test section. At the end of the wind tunnel test, Mach number and stagnation pressure are gradually decreased.…”

Section: Introductionmentioning

confidence: 99%

Application of a technique for reducing supersonic starting loads on internal wind tunnel balances

Vukovic

Damljanović

Ocokoljić

et al. 2022

Advances in Mechanical Engineering

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Higher than anticipated supersonic starting loads in the VTI T-38 wind tunnel were a consequence of higher than designed minimum start pressures. Initially, high starting loads limited the usefulness of the facility at high supersonic Mach numbers. Over time, it was established that several procedures and techniques had to be used cooperatively to diminish the problem. One of the techniques is the establishment of additional points of contact of the model and the support sting for the duration of the starting loads, so that a part of the aerodynamic loads is transferred to the sting through the added path, relieving the sensitive force balance. Some applications of this technique require dedicated mechanisms to operate, which was impractical for the VTI T-38 wind tunnel. To the contrary, the implementation of the idea in the VTI T-38 wind tunnel relies on using suitable inserts to make the clearance between the model and the sting such that model-sting contact is forced to occur during the start and stop phenomena, but not during the measurement phase of the test. For typical model configurations, transient starting and stopping loads can be reduced by more than 50%.

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Prediction of total pressure characteristics in the settling chamber of a supersonic blowdown wind tunnel

Abstract: stagnation pressure rapidly builds up and approaches the pressure in the storage tank. Predictions show an alarming rise in free stream dynamic pressure during transition from Mach 1 to 4 and vice versa, which needs to be verified through measurements.

Cited by 9 publications

References 0 publications

A technique for reducing supersonic transient loads on internal wind tunnel balances

A technique for reducing supersonic transient loads on internal wind tunnel balances

Numerical evaluation on aerodynamic design of pressure-regulating valve in trisonic intermittent wind tunnel

Application of a technique for reducing supersonic starting loads on internal wind tunnel balances

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