MAS117 - Thermodynamics, autumn 2024 Submission 3/Compulsory practice No. 3-deadline for submission Monday 23/9 at 18 The tasks count equally. You must reach at least 40% of the entire submission to have the submission approved. Draw a sketch and a process diagram if necessary. Write down important assumptions that must be assumed so that the tasks can be solved. 3.1 Complete the table! The substance is water. Show your calculations and list which tables you have used. 'Description of the condition' means that one should note whether the system is, for example, subcooled or in a saturated vapor phase etc. Condition T, °C P, kPa h, kJ/kg x Description of the condition 400 0.8 " 175 2 1800 0.0 3 100 45 250,700 1200 3477.0 3.2 A tank with a fixed volume of 30 liters contains 0.2 kg of the refrigerant R-134a. At start the pressure is 100 kPa. Heat is added to the tank and the pressure increases to 180 kPa (final state). a) Determine the vapor quality of R-134a at the start. b) Determine the temperature in the final state in °C. c) Draw a Pv diagram of the process and show the states and the process curve relative to it the saturation curve. 3.3 A piston-cylinder device initially contains steam at 5 MPa, which is superheated by 36.06°C. The piston-cylinder device is equipped with "stoppers", see figure below the task text. The steam is cooled at constant pressure until the piston settles on the stops and the cylinder now contains saturated liquid water. The cooling continues until the temperature in the cylinder is at 190°C. Find: a) temperature at the start in °C, b) the enthalpy change per unit mass of the steam when the piston has reached the stops, and c) the pressure in the final state in kPa and possibly the steam quality if the state is a saturated steam-liquid mixture. vanndamp 5 MPa Piston-cylinder device with stoppers (task 3.3) 3.4 2 kg of saturated liquid water at 120°C is heated in a piston-cylinder device with a variable load on the piston (meaning that the pressure is not constant in this process) until the volume of the water is five times greater compared to the volume at the start. In the final state, there is only saturated water vapor in the system. a) Calculate the volume of the water at the start in °C. What is the pressure at the start in kPa? b) Find temperature and pressure at the end of the process in °C and kPa respectively. c) Calculate the change in the water's internal energy in kJ in this process. d) Draw a Pv diagram of the process and show the states and the process curve relative to it the saturation curve. Draw the isotherms (lines of constant temperature) that pass through the initial and final states.

MAS117 - Thermodynamics, autumn 2024 Submission 3/Compulsory practice No. 3-deadline for submission Monday 23/9 at 18 The tasks count equally. You must reach at least 40% of the entire submission to have the submission approved. Draw a sketch and a process diagram if necessary. Write down important assumptions that must be assumed so that the tasks can be solved. 3.1 Complete the table! The substance is water. Show your calculations and list which tables you have used. 'Description of the condition' means that one should note whether the system is, for example, subcooled or in a saturated vapor phase etc. Condition T, °C P, kPa h, kJ/kg x Description of the condition 400 0.8 " 175 2 1800 0.0 3 100 45 250,700 1200 3477.0 3.2 A tank with a fixed volume of 30 liters contains 0.2 kg of the refrigerant R-134a. At start the pressure is 100 kPa. Heat is added to the tank and the pressure increases to 180 kPa (final state). a) Determine the vapor quality of R-134a at the start. b) Determine the temperature in the final state in °C. c) Draw a Pv diagram of the process and show the states and the process curve relative to it the saturation curve. 3.3 A piston-cylinder device initially contains steam at 5 MPa, which is superheated by 36.06°C. The piston-cylinder device is equipped with "stoppers", see figure below the task text. The steam is cooled at constant pressure until the piston settles on the stops and the cylinder now contains saturated liquid water. The cooling continues until the temperature in the cylinder is at 190°C. Find: a) temperature at the start in °C, b) the enthalpy change per unit mass of the steam when the piston has reached the stops, and c) the pressure in the final state in kPa and possibly the steam quality if the state is a saturated steam-liquid mixture. vanndamp 5 MPa Piston-cylinder device with stoppers (task 3.3) 3.4 2 kg of saturated liquid water at 120°C is heated in a piston-cylinder device with a variable load on the piston (meaning that the pressure is not constant in this process) until the volume of the water is five times greater compared to the volume at the start. In the final state, there is only saturated water vapor in the system. a) Calculate the volume of the water at the start in °C. What is the pressure at the start in kPa? b) Find temperature and pressure at the end of the process in °C and kPa respectively. c) Calculate the change in the water's internal energy in kJ in this process. d) Draw a Pv diagram of the process and show the states and the process curve relative to it the saturation curve. Draw the isotherms (lines of constant temperature) that pass through the initial and final states.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.3DP

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