V. P. Fomichev

Thermal instability of glow discharge in the gas loop of CO2 laser with extended disk fans-heat exchangers

CO2 lasers with transverse discharge and convective gas cooling find ever-increasing application. On strategy in making such lasers more efficient radiators is increasing the rate of the gas flow through the discharge zone with the help of diametral disk fans-heat exchangers. The application of such fans-heat exchangers, however, entails serious difficulties related to the glow discharge-gas flow interaction. In the present study, we investigate the stability problem for volume discharge in the gas loop of a CO2 laser with diametral dis fans-heat exchangers.

Electric-discharge control over a vortex flow around bodies of revolution

The key feature of a flow around axisymmetric bodies at large angles of attack is the formation of a conic vortex flow, where a pair of primary vortices dominates (Fig. 1). With an increase in the ratio of the angle of attack α to the half-apex angle θ of the model vertex, the initial attached flow is transformed to a detached flow with the formation of a pair of symmetric stationary vortices. With a further increase in the parameter

Mathematical modelling of flow in disc friction LVAD pump

The need for blood circulation support systems in the treatment of chronic heart failure is constantly increasing as 20% of patients on the waiting list die every year. Despite the great need for mechanical heart support systems the use of available systems is limited by the high cost. Therefore, further research in the field of circulatory support systems is appropriate taking into account medical and technical requirements. One of the new research areas is viscous friction disk pumps for transporting liquids based on the Tesla pump principle. The experimental model of LVAD disk pump is developed. Analytical dependencies are obtained to optimize the hydraulic parameters of the pump. On their basis, the experimental model of LVAD disk pump was designed and created. The results of analytical and experimental studies of such a pump are presented.

Circular pump support of blood circulation in the human body

The need of circulatory support systems in the treatment of chronic heart failure is increasing constantly, as 20% of patients in the waiting list die every year. Despite the great need for mechanical heart support systems, using of available systems is limited by the expensiveness. In addition, there is no one system that is 100% responsible to all medical and technical requirements, and would be completely safe for patient. Therefore, further research in the field of circu-latory support systems, considering health and technical requirements is relevant. One of the new directions in the study are disc pumps of viscous friction for liquid transporting, based on the Tesla pump principle. The operation principle of pumps based on the phenomenon of the boundary layer which is formed on the disk rotating in a fluid. There are experimental studies results of models with different variants of the rotor suspension, the various forms and the number of disks, forms the pump housing. However, none of the above sam...

Operation features of the diametrical disc fan at low pressures

Operation of the diametrical disc fan was studied experimentally at low (5–50 torr) pressures in air. The effect of a drastic decrease in volumetric flow rate of the fan was revealed at pressures below 40 torr (flow rate crisis), what does not correlate with published data. The critical value of dimensionless parameter corresponding to flow transformation and formation of a closed flow inside a fan was determined and proved experimentally.

Space-saving electric-discharge CO2 laser of high (up to 14kW) radiation power with convective cooling of the working medium and gas pumping by an extended disc fan

The presented data are the results of the development of the continuous electric-discharge CO2 laser with the cross discharge and convective cooling of the active medium, with the power up to 14 kW. Extended disc fans are used for gas pumping, they are heat-exchangers at the same time. Preliminary results of gas flow-rate, heat-exchange and energy characteristics are reported. Some experimental results of laser cutting of thick sheets are given as well as the results of the numerical and experimental simulation of the laser cutting gas-dynamics.

Experimental study of plasma flow in a disk MHD channel under conditions of spontaneous formation of a current layer

The results of an experimental study of the plasma flow in a disk channel under conditions of strong hydromagnetic interaction are presented. It is shown that if the condition RemH02/8π≥0.2 is satisfied for the magnetic Reynolds number at some point of the stream, then a current layer develops at that point characterized by a high electric-current density and high conductivity and temperature. The formation of the current layer leads to strong local retardation of the stream, the appearance of a shock wave, and a number of other nonlinear hydromagnetic phenomena. The experimental results are in agreement with theoretical studies conducted earlier.

An investigation of the nonsteady interaction of a conducting gas cloud with a given electrical circuit

The behavior of a cloud of conducting gas obtained from a coaxial plasma gun is investigated as it passes through a constant magnetic field. The way that this cloud interacts by induction with an electrical circuit coupled to an ohmic resistance is also studied. Paticular attention is paid to the study of the energy characteristics of the interaction (the energy generated in the ohmic resistance, relations between the plasma energy and Joule dissipation) as a function of the geometry and certain parameters of the electrical circuit. The process is analyzed theoretically for small values of the magnetic Reynolds number. Experimental and theoretical results are compared.