Development of a Novel Multi-Channel Thermocouple Array Sensor for In-Situ Monitoring of Ice Accretion

Abstract

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.

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

“…This study was performed to reinforce the abilities of the conceptually proven MCTCA [8] as an improved and accurate ice detection sensor. Firstly, the effect of the thickness of the resin layer was quantitatively studied based on heat conduction theory.…”

“…This helps to avoid any parasitic voltage contributions due to the addition of a material with a different Seebeck coefficient if there is no isothermal zone available [13]. The MCTCA sensor employed in this study is similar in terms of its architecture, materials, size, and configuration compared to the previous study [8]. However, in this study, the insulating resin thickness was carefully controlled during the fabrication process since the resin thickness is a key factor to determine the sensor sensitivity [8].…”

“…Firstly, the applied resin layer between the MCTCA and ice layers delays and distorts measurement of surface temperature variations. However, the previous study [8] did not systematically quantify the effect of the thickness of the resin layer. Secondly, the MCTCA can currently only inform of the occurrence of icing events.…”

“…Although the previous study [8] proved the feasibility and showed various advantages of the MCTCA as an ice detection system, the following limitations were highlighted. Firstly, the applied resin layer between the MCTCA and ice layers delays and distorts measurement of surface temperature variations.…”

“…In a previous study, an ice detection sensor using a proprietary multi-channel thermocouple array (MCTCA) technology was suggested for wind turbine blades [8]. Thermoelements can be arranged in an array or grid configuration with each node spot-welded or soldered to produce a thermocouple (TC) junction.…”