Applied Engineering Letters

35-39

Authors: V. Mitrevski, S.Bundalevski, C.Mitrevska, T.Geramitcioski, V.Mijakovski

In this paper the experimental results of far‐infrared vacuum drying of apple slices were presented. The investigation of far‐infrared vacuum drying processes was conducted on the experimental set‐up that was designed to imitate industrial batch dryer. Apple slices were dried at various vacuum pressures and temperatures of heaters which were kept constant during the single experiments. Five well known thin layer drying models from scientific literature were used to approximate the experimental data of drying kinetics in terms of moisture ratio. For each model and data set, the statistical performance index and chi‐squared value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Aghbashlo gives the best results for approximation of experimental drying data of apple slices.

46-50

Authors: K. Popovski, C. Mitrevska, V. Mitrevski, I.Popovski

In this paper the lamella heat exchangers were presented. They are used for water and air as operating mediums, and can be differentiated by the shape of the ribs. The one has sinuous type of ribs, while the other one has flat lamella ribs. Better heat transfer can give the exchanger with higher values of coefficient αr and factor ja. A comparison between both types of heat exchangers is made with reference to air velocity in the minimum flow cross ‐ section and Reynolds' number.

57-60

Authors: Y.A. Kuznetsov, V.V. Goncharenko, L.V. Kalashnikova, S.V. Strebkov , A.P. Slobodyuk, A.V. Bondarev

The article is devoted to the performance restoration technology development of the aluminum radiator of tractor «John Deer 7830». The distinctive feature of the suggested technology is cold gas spraying application, which provides air tightness restoration of the radiator made of thin‐walled aluminum parts and having complicated form that causes troubles to technological operation fulfilment. The carried out experimental investigations resulted in determining rational technological parameters of gas dynamic spraying: nozzle angle of the facility and the distance from the nozzle exit to the spraying surface, providing optimal mechanical characteristics of the repair coating.