Václav Dvořák

Shape optimization of the current body located in the cooling canal

The contribution is the second step of the optimization process introduced on AMEE’13 where the position of cooling canal was searched. In this paper the outward shape of the regulation current body located in the axis of the system is optimized to obtain required temperature on the outward surface of the tube. The algorithm was designed and debugged for simplified model, in which the plunger is replaced by the tube, which is surrounded by thermal source representing cooled glass moulded piece from outward, and the cooling water of temperature 15°C on input flowing through. The state problem is formulated as a stationary heat conduction process. The cost functional is taken as the second power of L2 distance of temperature from the given constant value on the outward boundary of the tube. The results of the numerical optimization to three required target temperatures 700, 750 and 800°C of the outward tube surface together with the distribution of temperatures on the interface between the tube and the heat...

Numerical solution of optimal design for axisymmetrical cooling canal

In this article we investigate the problem of shape optimization of the cooling cavity of the plunger used in the forming process in the glass industry. The paper deals with finding the algorithm for optimization of the shape of inner canal of plunger in such a way, that its outward surface, which realizes cooling of moulded piece, is attained constant set temperature. The results of the numerical optimization to three required target temperatures 700, 750 and 800°C of the surface Γ1 together with the distribution of temperatures on the interface Γ1 between the body and the heat source before and after the optimization process are presented.

Air to Air Ejector with Various Divergent Mixing Chambers

The article deals with experimental investigation of subsonic air to air ejector with various configurations of the mixing chamber and the diffuser. A constant mixing chamber, 2° and 4° divergent mixing chambers and 6° diffuser were applied to find differences in the mixing process. Characteristics of the ejector, static pressure distributions and pressure fluctuations were measured to find how the different shape of the mixing chamber affect the efficiency of mixing processes. Pressure fluctuation increased rapidly while the ejection ratio was higher than 1.25 and the highest efficiency of the ejector was obtained when using configuration 4-4-6.

Testing of Materials for Heat and Moisture Transport

The article deals with testing materials for using in enthalpy exchangers. The purpose of the enthalpy heat exchangers is to transport the heat and moisture together. Such heat exchangers are used in heat and ventilation air conditioning units. There are several methods how to test transport of moisture through material used in textile industry. However, these methods are not suitable for testing of materials, which are considered to be in heat exchangers. Methods for testing of moisture transport are usually based on free convection around membrane, which separates spaces with air of low humidity and air saturated with water. The free convection does not occur in heat exchangers and moisture varies in wide range. Therefore we developed and tested a devise to simulate moisture transport in enthalpy heat exchangers with plates, where co-current and countercurrent occur. With the help of this device, we could compare materials and evaluate the influence of the surface structure, which affect the boundary layers and heat and mass transport, when the flow is tangential to the material surface. We could also investigate the effect of flow velocity and humidity. The methods of evaluation are discussed and some results are presented.