HTTA 2026 06 17 with solutions

Page 1

Heat Transfer and Thermal Analysis - A.A. 2025/26 - Date 17/06/2026 VERY IMPORTANT: the answers must be written on the “Results” paper sheet, not on this text. Only the “Results” paper sheet must be uploaded and will be evaluated. NOTES: ˆStudents attending the 5 CFU course may have some different questions in part A. ˆFor the exercise queries, in case none of the multiple-choice answers the exercise matches the result you get, write your own result instead of marking an answer (so that in case we did a mistake and your answer is correct you can get the related points). ˆStudents having right to a test reduction should answer only to: all part A questions; queries 1, 2, 3 of the part B exercises. Part A 1) During a transient heat exchange process between a solid body and a fluid, that can be described with the lumped parameter approach neglecting radiation, the characteristic time of the phenomenon is: A*Directly proportional to the thermal capacitance of the body and inversely proportional to the convective heat transfer coefficient. BInversely proportional to the thermal capacitance of the body and directly proportional to the convective heat transfer coefficient. CDirectly proportional to the thermal conductivity of the body and inversely proportional to its isobaric expansion coefficient. DInversely proportional to the thermal conductivity of the body and directly proportional to its isobaric expansion coefficient. 2) For a full cylinder, homogeneous and isotropic, with heat source, exchanging heat by convection with a fluid at uniform temperature under steady-state conditions, the first integration constant obtained when integrating the one-dimensional Poisson equation is: AAlways positive. BAlways negative. C*Always zero. DAlways equal to the maximum temperature…