PSI - Issue 33

Irina A. Bannikova et al. / Procedia Structural Integrity 33 (2021) 1146–1151 Author name / Structural Integrity Procedia 00 (2019) 000–000

1147

2

P S

spall strength of condensed matter

S

slope coefficient in the shock adiabatic equation for a continuous medium velocity of the free surface of a continuous medium amplitude of the velocity of the free surface of a continuous medium

V Sf V 0 U 0 ε˙* η* ε˙

initial electrical voltage at the power source strain rate at the front of the rarefaction wave strain rate at the compression wave front strain rate at the compression wave front

ρ 0

initial density of a continuous medium under normal conditions

Under intense short-term impacts, the behavior of the environment is insensitive to its state of aggregation, therefore, the physical mechanisms responsible for the response to the impact of the environment under these conditions should be similar. It is of considerable scientific interest to describe the behavior of liquids under intense short-term effects based on an analysis of the kinetics of fluctuations induced by structural transitions. In this paper, in continuation of the above works and works Efremov et al. (2020) an experimental study of surfactant solutions (proppant carriers - Guar and Surfogel) under shock-wave loading conditions was carried out. 1.1. Experimental routine The shock-wave loading was implemented on setup for an electric explosion of a wire (EEW) in a liquid, based on the ICMM UrB RAS Institute (Perm, Russia) (Bannikova et al. (2014)). Liquids (surfactant solutions – Surfogel and Guar) were provided by POLIEX JSC (Perm, Russia). The experimental setup of the EEW in a liquid consisted of a cylindrical cell (height 8.5 cm, diameter 24 cm, volume ~ 5 liters), with a conductor vertically installed in the center (length 20 mm, diameter 0.1 μm), a system of capacitors (C 0 = 0.022 ÷ 0.44 μF) a high voltage source (U 0 = 1 ÷ 30 kV), a wire discharge system, a grounding device, a shunt. The complex for measuring the velocity of the free surface of a liquid consisted of the VISAR interference system Martin Froeschner & Associates Optoelectronics FDVI Mark IV-3000 (USA), the Tektronix DPO 7254 Digital Phosphor Oscilloscope (USA) and the sensor with a membrane (titanium-coated foil, 1 cm in diameter). In the cell of the EEW the wire was installed in the center vertically and the sensor was installed at a certain distance X from the place of initiation of the EEW. The test liquid was poured into the cuvette. As a result of the discharge on the conductor from the capacitor system (C 0 = 0.44 μF) charged from the high voltage source (U 0 = 15 kV), a compression wave propagated in the liquid from the EEW in the radial direction. Signals were recorded using the VISAR measuring system. Using the developed computer program, 4 signals from the oscilloscope were processed and the velocity profile of the free surface of the continuous medium was constructed. Test tests were carried out in distilled water (X = 15; 35; 40; 45; 75 mm), guar (X = 35; 45 mm) and Surfogel (X = 35; 45; 60 mm). Despite the fact that the sensor was different from that presented in the work (Bannikova et al. (2014)) it also recorded several pulses: from a spark gap, from a wire explosion, and processes on the free surface of a liquid under the action of shock waves. It was not difficult to find the last signal, knowing the distance X and the time during which the sound wave must passed through the liquid (c 0 = 1480 m/s) (Bannikova et al. (2014)). 2. Results and discussion For distilled water, the shape of the free surface velocity profiles did not differ from those obtained earlier in Bannikova et al. (2014). At smaller distances X Fig. 1 shows the profiles for distilled water. The profile (X = 15 mm) contains oscillations that can be associated with the vibration of the sensor membrane itself. Almost every profiles at the rarefaction wave front ahead of the spall pulse. We associate them with a pre-destroyed state in a liquid, when air bubbles appear after the passage of a shock wave, the size of which is much smaller than a spall plate (formation of a cavity, bubble). On the profile (X = 35 mm), the amplitude of the spall pulse exceeds the amplitude of the compression pulse. Similar behavior was observed in water at smaller distances X by Bannikova et al. (2014). This is related, as shown numerically in the work of Utkin (2011), with the growth of the porous medium