SIMULATION OF DYNAMICS OF THE SWIVEL CONTROL NOZZLE WITH DOUBLE ELASTIC JOINT

In order to create control moments for the rocket, the design of modern solid propellant rocket engines uses swivel control nozzles with elastic support joint. The disadvantage of such a joint as the nozzle suspension is the high joint torque, which determines the high requirements for power and effort of steering actuators. In order to reduce these requirements, it is possible to use the design of a swivel control nozzle with a double elastic joint, known as a nozzle with double elastic seal. This nozzle is not used due to its design and operational complexity, particularly due to its tendency to oscillatory processes, as it is a dynamic system with two degrees of freedom. In the article numerical simulation of dynamics of transient modes at deviations on demanded angles of a swivel control nozzle with double elastic joint is considered. For this purpose the approximate nonlinear mathematical model of dynamics of this nozzle constructed by the Lagrange method is used. The results of numerical simulation of transients in the open loop channel of nozzle movement control at abruptly apply the constant effort of steering actuator are given. It is given the method of determination the values of rotation angles of the moving parts of a nozzle and the effort of a steering actuators corresponding to the required angle of rotation of the nozzle. For the given values of the design characteristics of the nozzle and the layout parameters of the nozzle-steering actuators system by numerical simulation it is established that an acceptable oscillation of transients for the nozzle with a double elastic joint can be achieved by increasing the viscosity resistance coefficients in its suspension. Significant influence on damping of oscillations in transient modes of dynamics of the swivel control nozzle of its damping joint moments is also shown.

Time Sequential Single-Cell Patterning with High Efficiency and High Density

Single-cell capture plays an important role in single-cell manipulation and analysis. This paper presents a microfluidic device for deterministic single-cell trapping based on the hydrodynamic trapping mechanism. The device is composed of an S-shaped loop channel and thousands of aligned trap units. This arrayed structure enables each row of the device to be treated equally and independently, as it has row periodicity. A theoretical model was established and a simulation was conducted to optimize the key geometric parameters, and the performance was evaluated by conducting experiments on MCF-7 and Jurkat cells. The results showed improvements in single-cell trapping ability, including loading efficiency, capture speed, and the density of the patterned cells. The optimized device can achieve a capture efficiency of up to 100% and single-cell capture efficiency of up to 95%. This device offers 200 trap units in an area of 1 mm2, which enables 100 single cells to be observed simultaneously using a microscope with a 20× objective lens. One thousand cells can be trapped sequentially within 2 min; this is faster than the values obtained with previously reported devices. Furthermore, the cells can also be recovered by reversely infusing solutions. The structure can be easily extended to a large scale, and a patterned array with 32,000 trap sites was accomplished on a single chip. This device can be a powerful tool for high-throughput single-cell analysis, cell heterogeneity investigation, and drug screening.

Hydrodynamic nonadhesive cell retention in a microfluidic circuit for stressless suspension culture

Cell collection based on deterministic lateral displacement (DLD) and cell circulation with a loop channel are two component technologies for stressless cell retention which have been developed with a view to working toward suspension culture in a microfluidic channel.

Refining Slag Treatment with Flotation Cell

In past years, the exploitation of mineral resource in our country was stressed on capacity and the solid waste recycle and innocent treatment was ignored. Much valuable metal is associated and coexist with waste, it is in difficult position for present technology to recycle valuable composition in that waste, which leads to valuable component loss and environment pollution. Therefore, the development and utilization of copper refining slag is in significance. In this paper, the advantages and difficulties to process refining slag by flotation method are discussed based on property analysis of copper refining slag. The refining slag is featured by high specific gravity, high concentration, and its particles distributing at both ends of small and large size. A flotation cell with special structure of barrier grid plate and multi-loop channel is developed for refining slag processing, which provides a proper way to solve the sediment problem during refining slag flotation. The application of CLF-40(effective volume,40m3) flotation cell for processing slag mixture from flash furnace and converter is expounded, the production index shows that the Cu grade is up to 27.18% at recovery of 83.93% when slurry concentrate being 70%

HLRW Management During MR Reactor Decommissioning in NRC “Kurchatov Institute”

A program of decommissioning of MR research reactor in the Kurchatov institute started in 2008. The decommissioning work presumed a preliminary stage, which included: removal of spent fuel from near reactor storage; removal of spent fuel assemble of metal liquid loop channel from a core; identification, sorting and disposal of radioactive objects from gateway of the reactor; identification, sorting and disposal of radioactive objects from cells of HLRW storage of the Kurchatov institute for radwaste creating form the decommissioning of MR. All these works were performed by a remote controlled means with use of a remote identification methods of high radioactive objects. A distribution of activity along high radiated objects was measured by a collimated radiometer installed on the robot Brokk-90, a gamma image of the object was registered by gammavisor. Spectrum of gamma radiation was measured by a gamma locator and semiconductor detector system. For identification of a presence of uranium isotopes in the HLRW a technique, based on the registration of characteristic radiation of U, was developed. For fragmentation of high radiated objects was used a cold cutting technique and dust suppression system was applied for reduction of volume activity of aerosols in air. The management of HLRW was performed by remote controlled robots Brokk-180 and Brokk-330. They executed sorting, cutting and parking of high radiated part of contaminated equipment. The use of these techniques allowed to reduce individual and collective doses of personal performed the decommissioning. The average individual dose of the personnel was 1,9 mSv/year in 2011, and the collective dose is estimated by 0,0605 man×Sv/year. Use of the remote control machines enables reducing the number of working personal (20 men) and doses. X-ray spectrometric methods enable determination of a presence of the U in high radiated objects and special cans and separation of them for further spent fuel inspection. The sorting of radwaste enabled shipping of the LLRW and ILRW to special repositories and keeping of the HLRW for decay in the Kurchatov institute repository.

The Comparative Study on Flow Field in Sensitive Element of Fluidic Gyroscope

In this paper, the airflow of two different chamber structures is analyzed contrastively in the sensitive element of fluidic gyroscopes. Using ANSYS-FLOTRAN CFD software, the finite element simulation is conducted by a series of procedures, such as two-dimensional model building of fluidic gyroscope, meshing, loads applying and equation solving, we calculate the two dimensional airflow distribution of rectangle chamber and streamline chamber in sensitive element of fluidic gyroscope. The results show that the airflow velocity of the exit section in the streamline chamber which is 28.87% of the nozzle velocity is higher than that in the rectangle chamber structure, so the streamline chamber structure brings airflow together to a certain extent, and it also reduces the airflow accumulation in the chamber and smoothes airflow within the loop channel, lastly velocity gradient change in the streamline chamber is greater than that in the rectangle chamber, and the resolution of fluidic gyroscope is better than that with rectangle chamber.

On Boundary Conditions for Cavitation CFD and System Dynamics of Closed Loop Channel

The unsteady two dimensional CFD for the cavitation in a orifice passage were carried out by using a commercial software ANSYS-CFX. The mass flow rate and the static pressure were controlled at the inlet and the outlet boundaries respectively. The CFD result showed periodic fluctuation of the cavitation flow. The time derivative of the cavitation volume showed relatively good agreement with the difference of the inlet and the outlet volume flow rate. The periodic fluctuation was ceased by the extension of the passage length downstream of the cavitation. The periodic fluctuation of cavitation flow was also induced by the fluctuation of the inlet volume flow rate or the fluctuation of the outlet static pressure. The dynamic flow behavior of the closed loop system including the orifice were analyzed by using the orifice cavitation CFD with the inlet and the outlet boundary conditions derived from the lumped parameter system dynamics for the tank, the pump and the pipes in the loop.