Saturated water vapor at 100 kPa is in a piston-cylinder device. At the initial state the piston is 0.2 m from the cylinder bottom. The water vapor is heated in a constant pressure process until the cylinder volume is doubled. Sketch this process on P-v and T-v diagrams. Find the final distance from the piston to the cylinder bottom and the final temperature.

Problem 2 Consider a process during which 500 grams of saturated liquid water at 7 bar are heated under constant pressure to a final volume of 100 liters. a) Prove that at the final state the water appears as a mixture of liquid a vapour. b) What is the temperature at the final state? What was the temperature change during the process?

A 1 m diameter cylinder, 1 m long, is maintained at 800 K and has an emissivity of 0.65. Another cylinder, 2 m in diameter and 1 m long, encloses the first cylinder and is perfectly insulated. Both cylinders are placed in a large room maintained at 300 K. Calculate the heat lost by the inner cylinder.

The work done when a gas is expanded in a cylinder is -220 J. A heat transfer of 190 J occurs from the surrounding to the gas. Calculate ∆E of the gas in J.

(5)An insulated piston-cylinder device contains 15 L of saturated liquid water at a constant pressure of 950 kPa. Water is stirred by a paddle wheel while a current of 15 A flows for 28 min through a resistor placed in the water. If 64% of the liquid is evaporated during this constant pressure process and the paddle-wheel work amounts to 600 kJ, determine the voltage of the source. Also, show the process on a P-v diagram with respect to saturation lines. H,0 P= constant W. W.

Question 1.2 A helical coil cooler is used to cool 0.5 kg.s¹ of hot oil from 100°C down to 40°C. Cooling water with an inlet temperature of 10°C flows inside the coiled tube. The specific heat of the oil is 2 kJ.kg¹.K¹, the specific heat of the water is 4.2 kJ.kg¹.K¹, and the density of water is 1000 kg.m. a) Determine the lowest possible cooling water flow rate. (0.48 kg.s¹) b) Determine the inside diameter of the tube if a cooling water flow of 1.5 times the minimum is used, and the recommended flow velocity is 1 m.s. Select an appropriate tube from the following standard sizes: Outside diameter (mm) Wall thickness (mm) 30 1.5 35 2.0 40 2.0 45 2.5 50 3.0 c) For a heat transfer coefficient of U = 800 W.m2.K, determine the heat transfer surface area and the tube length of the heat exchanger. The oil inside the tank is mixed by a stirrer and the oil temperature at any location in the tank can be assumed to be equal to the oil outlet temperature. (Area = 4.12 m², length = 39.7 m)

8. 1.8-m³ rigid tank contains steam at 220 °C. One-third of the volume is in the liquid phase and the rest is in the vapor form. Determine (a) the pressure of the steam, (b) the quality of the saturated mixture, and (c) the density of the mixture.

The work for irreversible compression of an ideal gas in a piston-cylinder system is the work for reversible compression to the same final pressure. a) higher than b) lower than c) the same as d) We need more information