Raccolta domande teoriche

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Examples theory questions for the HTTA course - A.Y. 2014-15 Heat Transfer and Thermal Analysis A.Y. 2014/15 Examples of theory questions, short and long Short questions (part A of the exam test) 1. Conduction • Write the expressions of the temperature and heat flux profiles in a flat plate (having constant conductivity) with heat source, as a func- tion of the orthogonal coordinate and of the fixed temperatures on the boundary surfaces. • Write the expressions of the temperature and heat flux profiles in a hollow cylinder (having constant conductivity) with no heat source, as a function of the radius and of the fixed temperatures on the boundary surfaces. • Write the general equation for conduction in a medium having constant conductivity • Write the general equation for conduction in a medium having conduc- tivity which varies with temperature • Draw (qualitatively but with physical accuracy) the steady-state tem- perature profiles in a passive flat plate having fixed temperatures on the external surfaces and: 1) constant conductivity, 2) conductivity increasing with temperature, 3) conductivity decreasing with tempera- ture • Derive the general integrals giving the temperature and heat flux pro- files as a function of the radius for a very long, homogeneous cylinder with heat source. Comment the boundary condition on the axis in case of a full cylinder. • Draw (qualitatively but with physical accuracy) the steady-state tem- perature profiles in a passive flat plate made of 3 layers A, B, C and having fixed temperatures on the external surfaces, knowing that the thickness is the same for all layers and λA>λ B >λ C 1 Examples theory questions for the HTTA course - A.Y. 2014-15 • Write the finite difference approximations for the first and second de- rivatives of temperature with…