Technology and Development - Hydraulic
February 29 of 2012
EFFICIENCY MEASUREMENT OF HYDRO MACHINE BY THERMODYNAMIC METHOD
Shantaram.S. Patil / H.K. Verma / Arun Kumar
Paper published on PCH Notícias & SHP NEWS #51.
The thermodynamic method is an absolute method of measuring hydraulic efficiency of hydraulic machines based on the principle of conservation of energy, i.e. first law of thermodynamics. The efficiency is calculated directly from the specific hydraulic energy and specific mechanical energy equations. The temperature difference between the inlet and outlet of the machine is very small, typically of the order of a few milli-Kelvins. Hence it is a very difficult and critical task to measure the temperature rise accurately. High-resolution high-accuracy data acquisition system alongwith precision type temperature sensors are essential for temperature measurements.
Efficiency measurement using thermodynamic method has been carried out by the authors in laboratory, both on a turbine and a pump, using stable temperature sensors, electronic pressure transmitters and high-precision high-resolution data acquisition system. Thermo-wells are formed at inlet and outlet of the machine under test for simultaneous temperature measurement at both the points. High-precision RTDs of Pt-100 type (class 1/10 DIN, 0.03 ?C accuracy) are used for the measurement of temperatures.
The results of efficiency measurement of turbine and pump in laboratory using thermodynamic method have been found to be very satisfactory. The same instrumentation with suitable adaptation can be used for the efficiency measurement on site.
KEYWORDS: Hydraulic machine, Hydraulic efficiency, Thermodynamic method.