A Study on Comparison of Temperature Distribution between Aluminum and GFRP Mold under Carbon Spar-Cap Manufacturing Process

Abstract

In this study, temperature distribution as a function of the spar-cap thickness was numerically analyzed using a 20 kW wind carbon blade model. “Realizable k-ε”, which was adopted as a turbulence model for heat transfer analysis, was effective in convection and diffusion calculations. SC/TETRA, a commercial thermal fluid analysis software, was used to calculate the heat flow from the heat panel to the outside boundary of the simulation model. In order to derive the equation for the temperature between the mold surface and the top surface of the spar-cap, the temperature interval of the heat panel was 10 °C, and the range was from 60 °C to 110 °C. As a result, the temperature distribution of the top surface of the spar-cap was insufficient to cure the Carbon Fiber Reinforced Plastic (CFRP) because the heat did not reach from the mold heat panel to the top surface of the carbon spar-cap. To resolve the problem of heat loss, the equation was derived by dividing the temperature boundary conditions between the mold surface and the spar-cap top surface as a function of the thickness of the carbon laminates. The temperature unevenness in the spar-cap curing process was reduced using the improved boundary condition. In addition, the cases where GFRP and aluminum were applied to the upper mold of the heat panel were compared using the same analysis method. An improvement to reduce the temperature non-uniformity of the spar-cap top surface was studied to solve the non-curing issue of the carbon spar-cap under the manufacturing process.