Full exam for Heat Transfer and Thermal Analysis in the Aerospace Engineering degree programme at Politecnico di Milano. The document covers: Heat T ransfer and Thermal Analysis - A.Y. 2017/18 - Date 11/09/2018 Surname: Name: ID number: Signature: (“matricola” or person code) Part A 1. The surface tension between water and air is 72 mN/m. Calculate (writing the equation you use) the value of the pressure difference
Full exam for Heat Transfer and Thermal Analysis in the Aerospace Engineering degree programme at Politecnico di Milano. The document covers: Heat T ransfer and Thermal Analysis - A.Y. 2017/18 - Date 11/09/2018 Surname: Name: ID number: Signature: (“matricola” or person code) Part A 1. The surface tension between water and air is 72 mN/m. Calculate (writing the equation you use) the value of the pressure difference
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Heat T ransfer and Thermal Analysis - A.Y. 2017/18 - Date 11/09/2018 Surname: Name: ID number: Signature: (“matricola” or person code) Part A 1. The surface tension between water and air is 72 mN/m. Calculate (writing the equation you use) the value of the pressure difference between the inside and the outside of a bubble of air in water if the bubble has radius 5 µm. 2. Sketch a second surface mirror, evidencing in the drawing the working principle and stating why for a solar reflector it is better than a first surface mirror. 3. Place the following materials in ascending order of conductivity: rubber, air, iron, stainless steel, copper. 4. State the contributions to the pressure drop for a two-phase flow in a vertical duct having constant section. 5. Draw the temperature profiles T (x) for a counter-current heat exchanger having ˙CH > ˙CC. 6. Write the general expressions of temperature and heat flux as a function of the radius in a hollow cylinder in steady-state conditions and with heat source, before application of any b.c.. 7. Write the cosine (or Lambert) law for a black body, stating the quantity indicated by each of the used symbols. Heat T ransfer and Thermal Analysis - A.Y. 2017/18 - Date 11/09/2018 - Part B INSTRUCTIONS - Read them very carefully! • test duration is 1 h 45’. After 35’ part A will be collected. If you finish part A in a shorter time, you can immediately move to part B; • you must answer to part A questions in the spaces provided after the questions themselves; remember also to fill in all the fields (surname, name, progressive number, ...) on the part A paper; • for part B, you can use only one foolscap paper for the final copy (additional papers will not be collected). On top-left of the first page of the foolscap paper you have to write (in a large…
First page of the document.
