Abstract: In order to obtaining the dynamic evolution image of Tungsten array for foam padding, and to research the form of interaction between Tungsten plasma and foam column, a shadow imaging system of four-frame ultraviolet probe laser (266nm)has been designed on 1MA pulse power device. The time resolution of the system is 2.5ns, and static space resolution is superior to 70μm. The radial shadowgraphy image reveals the whole process from the melting and expansion of solid wire to the interaction of the precursor plasma and the foam, from the pinch to rebound inflation. The image shows the continuous interaction of Tungsten plasma and foam in a form of “Raining" within a time of about 50ns, the plasma shell structure has not been found in the whole period of pinch. The quantitative analysis indicates the minimum pinching speed of the foam column is 1.0×106cm/s, and maximum pinching speed is 6.0×106cm/s, and the axial stagnation diameter is approx 1mm.
Abstract: Study fluid flow and heat transfer characteristics of
microchannel in a primary Cross-corrugated(CC) surface recuperators
with corrugations and without corrugations, using CFD method. The
pitch-over-height ratios P/H of Cross-corrugated (CC) surface is from
1.5 to 4.0, included angles β=75º. The study was performed using CFD
software FLUENT to create unit model and simulate fluid
temperature, velocity, heat transfer coefficient and other parameters.
The results from these simulations were compared to experimental
data. It is concluded that, when the Reynolds number is constant, if
increase P/H, j/f will decrease, also the decreasing trend will become
weak. Under the condition of P/H=2.2, if increase the inlet velocity j/f
will decrease; in addition, the heat transfer performance in surface
with corrugation will increase 10% compared to that without
corrugation. The study results can provide the basis to optimize the
design, select the type of heat transfer surface, the scale structure, and
heat-transfer surface arrangement for recuperators.