Fuel integrity evaluation method for BWR-6 plant Kuosheng during ATWS events

Anticipated Transients without Scram (ATWS) are evaluated to demonstrate that during ATWS the fuel’s integrity prevents fission product release, and that the safety features the BWR-6 plant is equipped with mitigate the ATWS event. For analyzing this scenario, a RETRAN-3D system model and hot channel model of Kuosheng NPP have been developed. From all possible events those are analyzed where the main steam isolation valves close (MSIVC) when the reactor is operating at rated power conditions. For cases with low core flows this results in higher peak cladding temperatures and thicker oxidation thicknesses. All results confirm the ATWS acceptance criteria. For sensitivity cases, increasing the boron concentration of standby liquid control system (SLCS) or injecting boron of SLCS earlier were investigated. The results show, that these measures cannot decrease the PCT value immediately, but can shorten the period of peak cladding temperature over 850 °C which results in smaller oxidation thickness.

Circumferential Combustor Cavity Flow Fields With Decreasing Core Flow

Prior research into Ultra Compact Combustors (UCC) showed an axial length savings compared to traditional gas-turbine combustors. This savings is achieved by swirling the reactants circumferentially in a recessed cavity around the outside diameter of the engine. A similar circumferential combustor is envisioned for a new engine configuration that positions the combustor outboard of a radial compressor and an inflow turbine. This configuration will offer an axial length savings for the entire engine, not just the combustor. The new engine configuration will not utilize a core flow path and thus requires all engine air from the compressor to pass through, or around, the combustor cavity. This report characterizes the cavity flow behavior as the core flow quantity was reduced from 80% of the total engine mass flow rate down to zero, representing the new engine configuration, while maintaining constant cavity mass flow rates. Velocity profiles were obtained with particle-shadow image velocimetry (PSV) in cold flow and with particle streak emission velocimetry (PSEV) in reacting flow experiments. The cold flow results showed that the core flow produced a suction and removed fluid from the circumferential cavity resulting in a lower cavity mass flow rate. This behavior resulted in lower circumferential velocities at higher core flow percentages and the fastest cavity velocity with zero core flow. Reacting flows produced a similar result with the fastest cavity velocities achieved at reduced, but non-zero core flows, and the slowest velocities at the highest and zero core flows. Overall, it was found that there was no negative impact on performance from the removal of the core flow that would prohibit development of the new engine.

Recent progress in identification of the geomagnetic signature of 3D outer core flows

A summary of methods yielding information about the generation and configuration of the geomagnetic main field is presented with special focus on complications concerning these methods. A global source model constructed with the help of machine learning (and deep learning) is proposed to mitigate these issues, in particular the uncertainties caused by vigorous convection and small scale fields.

Experimental Study on Heat Transfer of Leading Edge Film-Cooling With Counter-Inclined Cylindrical and Laid-Back Holes

The heat transfer coefficient of counterinclined film holes fed by different intake structures on the turbine vane leading edge (LE) model is experimentally investigated in this paper. A semicylinder model is adopted to model the vane leading edge, which is arranged with one single row of film holes per side, which are located from the stagnation at a 15-deg angle. The four leading edge models, which are the combinations of the hole-shapes (cylindrical hole and laid-back hole) and intake structures (plenum and impingement), are tested at four blowing ratios M. The contours of the heat transfer coefficient, which are characterized by the Frössling number Fr, since it includes the Reynold number effect, are acquired by the transient measurement technique based on double thermochromic liquid-crystals (LCs). The lateral-averaged Fr of the nonfilm-cooled model is provided by using the same experimental platform with an identical main-flow condition. It is then compared with the published data, which indicates the reliability of the present transient measurement techniques. The results illustrate that a core region with a higher heat transfer appears in the hole-exit downstream, and its distribution is slightly skewed to the inclination direction of the film holes. The shape of the high heat transfer region gradually inclines in the spanwise direction as M increases. The heat transfer in the region where the jet core flows through is relatively low, while the jet edge region is relatively high. The effect of impingement leads to the outflow of each hole becoming increasingly uniform, which can reduce the difference in the heat transfer between the region where the jet core flows through and the jet edge. The heat transfer strength may increase due to the intense turbulence caused by the introduction of the impingement. Compared with the cylindrical hole, the laid-back hole has a spanwise expansion feature, which makes the shape of the high heat transfer region wider in the spanwise direction and increases the heat transfer level. Additionally, the magnitude of the enhancement increases with an increasing M.

Multifunctional responsive fibers produced by dual liquid crystal core electrospinning

Multifunctional responsive fibers are produced by dual-core coaxial electrospinning, with distinctly different liquid crystals in adjacent core flows.