Experimental study on ice intensity and type detection for wind turbine blades with multi-channel thermocouple array sensor

A multi-channel thermocouple array (MCTCA) sensor has been fabricated and tested for in-situ monitoring of the temperature variation under icing conditions for wind turbine blades. The obtained temperature data is analysed as a tool to predict the icing intensity (g m−2) and type (rime and glaze) with respect to the temperature gradients. The tests are performed in an environmental chamber with a water spraying system. The temperature of the chamber is set to −15 °C to ensure the sprayed water is supercooled before reaching the apparatus surface. Based on the various tests, the following conclusions can be drawn. Firstly, the MCATA can successfully predict icing events where the maximum temperature rise is monitored as 11.9 °C for 2 mm and 9.8 °C for 3 mm resin thicknesses with the same amount of accumulated ice. Secondly, this study suggests the temperature change per unit mass as an indicator of the ice intensity. Severe icing events can be expected when the indicator converges to zero. Finally, this study found that the surface temperature gradient is changed over time due to the amount of latent heat released where the two different environmental conditions, −15 °C and −5 °C, are considered. It could be used to evaluate the ice types.</p

Development of a novel multi-channel thermocouple array sensor for in-situ monitoring of ice accretion

A test was performed to determine the efficacy of a novel multi-channel thermocouple temperature sensor employing “N+1” array architecture for the in-situ detection of icing in cold climates. T-type thermoelements were used to fabricate a sensor with six independent temperature sensing points, capable of two-dimensional temperature mapping. The sensor was intended to detect the high latent heat of fusion of water (334 J/g) which is released to the environment during ice formation. The sensor was embedded on a plywood board and an aluminium plate, respectively by an epoxy resin. Three different ice accretion cases were considered. Ice accretion for all cases was achieved on the surface of the resin layer. In order to analyse the temperature variation for all three cases, the first 20 s response for each case was averaged between three cases. A temperature increase of (1.0 ± 0.1) °C and (0.9 ± 0.1) °C was detected by the sensors 20 s after the onset of icing, attributed to the latent heat of fusion of water. The results indicate that the sensor design is well-suited to cold temperature applications and that detection of the latent heat of fusion could provide a rapid and robust means of icing detection