Internal insulation and solid propellant behavior measured by ultrasonic method on solid rocket motors

The development of an ultrasound technique for precisely measuring the instantaneous regression rate of a solid-rocket propellant under transient conditions is reviewed. The technique is used to measure the burning-rate response of several solid propellants to an oscillatory chamber pressure with a frequency of up to 300 Hz. This measurement is known as the propellant's pressure-coupled response function and is used as an input into rocket stability prediction models. The ultrasound waveforms are analyzed using cross-correlation and other digital signal processing techniques to determine burning rate. Digital methods are less prone to bias and offer greater exibility than other techniques previously used. The resulting data are corrected for compression effects. The effects of a changing thermal pro le on the measurement are discussed. Other phenomena that may corrupt the measurement, such as surface roughness, are also covered. Results of the experiments are compared to data from two other measurement techniques: a T-burner and a magnetic owmeter. Nomenclature A= quasi-steady gas-phase and solid-phase reaction layer, homogeneous, one-dimensional solid (QSHOD) parameter, .@ P r=@ T s / p A = amplitude, or envelope function a T = temperature shift factor B = QSHOD parameter, .@ P r=@ T 0 / p C = group velocity C 1 , C 2 = Williams-Landel-Ferry (see Refs. 28 and 51) constants, see Eq. (26) c = phase speed d = particle diameter f = frequency, or arbitrary function G = spectral density function, or shear modulus g = arbitrary function h = propellant height i = .¡1/ 1=2 K = bulk modulus k = wave number M = bulk longitudinal modulus n = QSHOD parameter, .@ P r=@ p/ T0 n s = QSHOD parameter, .@ P r=@ p/ Ts P = principal part p = pressure R = cross-correlationfunction R = response function P r = burning rate T = period, or temperature t = time u = particle displacement in wave equation w = integration variable x = distance ® = attenuation coef cient 1t = round-trip time 1x = propellant thickness ± = round-trip time ±² = experimental erroŗ = QSHOD condensed phase eigenvalue, de ned in Eq. (21) º = Poisson's ratio » = thermal boundary-layer thickness ½ = density Ä = nondimensional frequency ! = frequency j j = magnitude of a complex number arg ² = phase of a complex number h i = averaged quantity Subscripts eff = effective f = nal value i = imaginary part, or initial value r = real part s = surface 0 = reference value Accents and Superscripts O = composite signal N = steady-state quantity 0 = unsteady quantity Q = Hilbert transform of a signal

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“…Then the t can be extrapolated out to when the propellant burns out, and the term in Eq. (16) proportional to web thickness is zero.…”

Section: Pressure Correctionmentioning

confidence: 98%

“…(Since then, researchers at ONERA reported the use of digital techniques in a study of rocket insulation behaviorusing ultrasound. 16 ) These digitaltechniquesoffer superior signal detection compared to analog methods and are much more exible.…”

mentioning

confidence: 99%

Evaluation of Ultrasound Technique for Solid-Propellant Burning-Rate Response Measurements

Murphy

Krier

2002

Journal of Propulsion and Power

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“…The thermocouple is embedded in the insulation layer to measure the dynamic ablative process of the head insulation layer. Cauty et al [ 29 ] employed an ultrasonic method to assess the dynamic ablative process of the insulation layer in the engine. Sakai et al [ 30 ] described an ablation sensor that can measure ablation fronts in real-time and in situ, but the measurement is limited to a small region.…”

Section: Introductionmentioning

confidence: 99%

Instantaneous Ablation Behavior of Laminated CFRP by High-Power Continuous-Wave Laser Irradiation in Supersonic Wind Tunnel

Wang

Song

et al. 2023

Materials

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Experimental and numerical investigations of the instantaneous ablation behavior of laminated carbon fiber-reinforced polymer (CFRP) exposed to an intense continuous-wave (CW) laser in a supersonic wind tunnel are reported. We establish an in situ observation measurement in the experiments to examine the instantaneous ablation behavior. The surface recession depth is calculated by using the Particle Image Velocimetry (PIV) method, taking the ply angle of laminated CFRP as a reference. A coupled thermal-fluid-ablation numerical model incorporating mechanisms of oxidation, sublimation, and thermomechanical erosion is developed to solve the ablation-through problem of multilayer materials. The results show that the laser ablation depth is related to the laser power density, airflow velocity and airflow mode. Thermomechanical erosion is the primary ablation mechanism when the surface temperature is relatively low and the cavity flow mode is a closed cavity flow. When the surface temperature reaches the sublimation of carbon and the airflow mode is transformed to open cavity flow, sublimation plays a dominant role and the ablation rate of thermomechanical erosion gradually decreases.

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Ultrasound measurement method: Errors, noise, and sensitivity

Cauty¹,

Éradès²

2000

Combust Explos Shock Waves

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Internal insulation and solid propellant behavior measured by ultrasonic method on solid rocket motors

Cited by 4 publications

References 3 publications

Evaluation of Ultrasound Technique for Solid-Propellant Burning-Rate Response Measurements

Evaluation of Ultrasound Technique for Solid-Propellant Burning-Rate Response Measurements

Instantaneous Ablation Behavior of Laminated CFRP by High-Power Continuous-Wave Laser Irradiation in Supersonic Wind Tunnel

Ultrasound measurement method: Errors, noise, and sensitivity

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