Q. For sand-casting a steel rectangular plate with dimensions 80 mm × 120 mm × 20 mm, a cylindrical riser has to be designed. The height of the riser is equal to its diameter. The total solidification time for the casting is 2 minutes. In Chvorinov’s law for the estimation of the total solidification time, […]
For sand-casting a steel rectangular plate with dimensions 80 mm × 120 mm × 20 mm Read More »
Q. Taylor’s tool life equation is used to estimate the life of a batch of identical HSS twist drills by drilling through holes at constant feed in 20 mm thick mild steel plates. In test 1, a drill lasted 300 holes at 150 rpm while in test 2, another drill lasted 200 holes at 300
Q. Following data correspond to an orthogonal turning of a 100 mm diameter rod on a lathe. Rake angle: +15o ; Uncut chip thickness: 0.5 mm; nominal chip thickness after the cut: 1.25 mm. The shear angle (in degrees) for this process is ______________(correct to two decimal places). Ans:
Following data correspond to an orthogonal turning of a 100 mm diameter rod on a lathe Read More »
Q. The true stress (in MPa) versus true strain relationship for a metal is given by σ = 1020e 0.4 The cross-sectional area at the start of a test (when the stress and strain values are equal to zero) is 100 mm2. The cross-sectional area at the time of necking (in mm2) is ________________(correct to two decimal places)
The true stress (in MPa) versus true strain relationship for a metal is given by Read More »
Q. A test is conducted on a one-fifth scale model of a Francis turbine under a head of 2 m and volumetric flow rate of 1 m3/s at 450 rpm. Take the water density and the acceleration due to gravity as 103 kg/m3 and 10 m/s2, respectively. Assume no losses both in model and prototype
Q. Ambient air is at a pressure of 100 kPa, dry bulb temperature of 30 oC and 60% relative humidity. The saturation pressure of water at 30 oC is 4.24 kPa. The specific humidity of air (in g/kg of dry air) is_______(correct to two decimal places). Ans: 16.00 – 16.50
Q. A standard vapor compression refrigeration cycle operating with a condensing temperature of 35oC and an evaporating temperature of -10 oC develops 15 kW of cooling. The p–h diagram shows the enthalpies at various states. If the isentropic efficiency of the compressor is 0.75, the magnitude of compressor power (in kW) is ________(correct to two decimal
Q. Air is held inside a non-insulated cylinder using a piston (mass M=25 kg and area A=100 cm2) and stoppers (of negligible area), as shown in the figure. The initial pressure Pi and temperature Ti of air inside the cylinder are 200 kPa and 400°C, respectively. The ambient pressure P¥ and temperature T¥ are 100 kPa and
Q. A 0.2 m thick infinite black plate having a thermal conductivity of 3.96 W/m-K is exposed to two infinite black surfaces at 300 K and 400 K as shown in the figure. At steady state, the surface temperature of the plate facing the cold side is 350 K. The value of Stefan- Boltzmann constant,
Q. A frictionless circular piston of area 10-2 m2 and mass 100 kg sinks into a cylindrical container of the same area filled with water of density 1000 kg/m3 as shown in the figure. The container has a hole of area 10-3 m2 at the bottom that is open to the atmosphere. Assuming there is
