Water at 30°C flows over a flat plate maintained at 90°C at a velocity of 10 m/s. Given the viscosity, thermal conductivity and Cp of water as 4.5 × 10-4 Pa.s, 0.65 W/mK, 4200 J/kg K. The thermal boundary layer thickness at 2 m from the leading edge of the plate is _____ mm.
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