SPECIAL AND EXTREME TRIPLE SHOCK-WAVE CONFIGURATIONSUDC 533.6.011.72 V. N. Uskov and M. V. ChernyshovTriple shock-wave configurations in steady supersonic flows of an inviscid perfect gas are considered. Triple configurations with special intensities of shock waves and extreme ratios of various flow parameters behind these configurations are determined.1. Object of the Study. Formulation of the Problem. A triple configuration (TC) of shock waves is the structure of gas-dynamic discontinuities in a supersonic flow, which consists of three shock waves (j i , where i = 1, 2, 3) and a tangential discontinuity τ possessing a common (triple) point T (Fig. 1). The initial-flow streamline that arrives at the triple point divides the flow into two parts, one of them passing through a system (sequence) of shock waves j 1 and j 2 , and the other passing only through one (basic or resultant) shock wave j 3 . The tangential discontinuity τ separates flows moving along it behind the shock waves j 2 and j 3 ; therefore, this tangential discontinuity is sometimes called the slip line.The classification proposed by Landau [1] for discontinuities with respect to the point T allows us to consider the shock wave j 1 to arrive at the triple point. The flow behind the shock wave j 1 is supersonic if there is the next shock wave j 2 , which can either arrive at the point T (Fig. 1a) or emanate from this point (Fig. 1c-e). In the case of a subsonic flow behind the shock waves j 2 (Mach number M 2 < 1) or j 3 (M 3 < 1), the directions of these shock waves in the vicinity of the point T do not allow us to state whether they are the reason for TC formation or the consequence of the latter.TC calculation in a flow with a certain Mach number normally requires setting the parameters of the incoming shock wave j 1 (e.g., the angle of its inclination to the free stream σ 1 or intensity J 1 , which is the ratio of static pressures ahead of the shock wave and behind it). TC formation is sometimes called the "branching" of the incoming shock wave. The triple configuration is determined by the following conditions of dynamic compatibility at the discontinuity: 1) equal static pressures (p 2 = p 3 ); 2) identical directions of flows separated by the discontinuity.Thus, a continuous supersonic flow in the TC transforms to a discontinuous flow consisting of two flows with different gas-dynamic parameters f 2 and f 3 behind the TC, which are separated by a discontinuity. The ratios I f = f 2 /f 3 and the differences ∆f τ = (f 2 − f 3 )/f (f stands for flow parameters ahead of the triple point) characterize flow nonuniformity caused by different degrees of transformation of initial-flow parameters in a system of two shock waves and in a single basic shock wave. If the TC is formed in a nonuniform initial flow or the shock waves j i are curved, the conventional conditions on the discontinuity τ are supplemented by differential conditions [1]: 1) equal curvature of the streamlines adjacent to the discontinuity τ ; 2) equal derivatives of static pressure o...

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Physico-chemical behavior of vanadium in chloride melts was studied using high temperature electronic absorption spectroscopy and spectroelectrochemistry. Dissolution of VCl 3 in molten chloride leads to the formation V(III) species, VCl 6 3-. Vanadium(II) complex ions VCl 6 4-are formed during electroreduction of vanadium(III)-containing melts and vanadium metal anodic dissolution. V(II) chloro-species slowly react with silica to form an oxygen-containing insoluble phase. Due to high volatility of VCl 4 oxygen-containing vanadyl species, VOCl 4 2-, is the only stable form of V(IV) in fused chlorides. It is formed when V 2 O 5 , V 2 O 4 or V 2 O 3 react with HCl. Electroreduction of vanadyl complexes leads to the formation of insoluble oxygen-containing vanadium(III)species, whereas electrochemical oxidation has no effect on vanadium speciation, VO 3+ /VO 2+ red-ox potential is more positive than Cl 2 /Cl -. Further oxidation VO 2+ species gives vanadate anions. The electronic absorption spectra of soluble vanadium species were measured in 3LiCl-2KCl, NaCl-KCl and NaCl-2CsCl mixtures at 450-750 0 C.

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