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Course of ADVANCED MANUFACTURING PROCESSES Proff. Michele Monno – Barbara Previtali – Matteo Strano SURNAME NAME PERSONAL ID Exam - January 24th 2019 Exercise n. 2 – technological problem To cut a large concrete block on a construction site, it is thought to use an ASJ (Abrasive Suspension Jet) cutting system. The ASJ system can be equipped with a single Discharge Vessel (DV), with no internal separator between water and abrasive, or with 2 or more vessels, each with 200 liters capacity, equipped with internal separation piston and valves for shifting from one tank to another After some tests using a 100 MPa HP pump that allows water flow up to 200 liters/min, it is estimated that the hydro-abrasive jet should have an exit diameter of 3 mm (with an discharge coefficient Cd = 0,9); the duration of the cut, without interruptions for the refill of water/abrasive, should be no more than 30 min, with an initial abrasive concentration in the DV of 50% and a final equal to 15%. During the rectilinear cutting, the head will remain in a fixed position and the concrete block will be moved thanks to a special electrically powered carrier. Under the indicated conditions, determine for the case of single vessel (with by-pass): 1. The minimum volume of the vessel (VDV) compatible with the assigned parameters. 𝑸𝑫𝑽 [l/min] 𝑽𝑫𝑽,𝒎𝒊𝒏 [l] 2. The initial concentration of abrasive in the vessel, if this has double the minimum volume. 𝑽𝑫𝑽 [l] 3. Assuming a linear variation of the concentration, calculate the amount of abrasive necessary for the cutting (abrasive specific weight = 2 kg /liter) Abr [kg] Furthermore, for the case of Indirect Pumping, determine: 4. Amount of abrasive necessary to complete the cut. Abr [kg] 5. Optimal number of tanks to be used taking into account that the…