Jolanta Stacharska-Targosz

In this paper the analysis of performance characteristics of a cross flow fan working as an element of the unit incorporating heat exchanger as well as performance characteristics of the unit are presented. These experimental results were basic for consideration of pressure losses arising as an effect of direct connection of a cross flow fan and a heat exchanger located in the charging zone of the fan as a resistance. Analysis of an influence of rotational speed variation as well as a medium temperature on aerodynamic characteristics of heat exchanger let to propose a method for the local pressure loss estimation.

In this paper some selected problems dealing with an influence of different throttling conditions on the flow structure inside a cross flow fan working in a unit incorporating a heat exchanger as well as on aerodynamic performances of a cross flow fan and unit have been studied. Different experimental and numerical methods have been used to verify and confirm selected flow phenomena. The local pressure loss as an effect of a heat exchanger resistance has been estimated taking into consideration some experimental results confirmed by the Finite Volume Method computation.

In this paper the problem of volumetric flow rate regulation is considered. The change of angular position of an element mounted axially inside of the cross flow fan impeller creates different aerodynamic performances: yt = f (j), ys = f (j) at the same rotational speed and in consequence the qualitative diversification of fan operation is obtained. It gives possibility to use a cross flow fan for several applications depending on an actual requirement respecting to volumetric flow rate or pressure coefficient. The shape of inner element as well as its angular position have an important influence on the flow structures so a method of volumetric flow rate control without necessity of rotational speed change is proposed. This way of cross flow fan flow rate control, commonly made with use of frequency converter, seems to be more effective for reduction of an energy consumption and gives an evidenteconomic advantage.