• MACHINES

    DESIGN AND PERFORMANCE ANALYSIS OF OBSTRUCTION FLOW MEASUREMENT DEVICES FOR LOW AIR FLOW RATES USING CFD ANALYSIS

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 4, pg(s) 143-148

    This study, considering need of fresh air in the air-conditioning system in a small residence, geometrical dimensions of a flow nozzle and an orifice plate were determined by theoretical equations in the literature. The measurement performances of designed flow meters were compared with numerical method using Computational Fluid Dynamics (CFD). The measured air flow rate is in the range of 80-300 m3/h and Reynolds numbers at the inlet of flow meters are 12,000-46,000. The β ratio of designed flow meters is chosen to be  0.45  in order to avoid excessive increase of pressure drop. Three dimensional numerical models were created to control the accuracy of flow
    meters. The results from numerical solution show that permanent pressure loss in the orifice plate is 2.6 times greater than the flow nozzle. Lower pressure and energy loss occur in the flow nozzle compared to the orifice plate. In a system where continuous measurement for the purpose of velocity control of fans is carried out, it has been found that electric power consumption of the fans will increase by 4.85 W and 12.42 W, respectively, at the flow rates of 150 and 200 m3/h for flow nozzle.

  • MACHINES

    DESIGN OF A NEW FRANCIS TURBINE RUNNER FOR A REHABILITATION PROJECT IN TURKEY

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 9, pg(s) 11-14

    This study presents the rehabilitation project for the Francis turbine runner of Kepez 1 Hydroelectric Power Plant (HEPP) in Antalya, Turkey. The aim of rehabilitation is to increase the power and efficiency of the plant and solve the existing problems such as cavitation. Initially, the head and flow rate of the turbine are estimated. Within the scope of this study, the design parameters which are necessary to obtain better cavitation characteristics and higher power and efficiency, are determined and computational fluid dynamics (CFD) is utilized to design a new runner geometry for better performance. The results of the CFD simulations are compared to the simulation results of the existing runner geometry which was obtained from the plant and scanned using laser scanning. The results show that cavitation characteristics and the efficiency, as well as the power of the HEPP are improved.