Engineering Question
BEng Aircraft Maintenance – Batch: March 2024 Engineering Science 2 – EA210MED Assignment 2 – Thermofluids Scenario: You have recently joined ABC Design Company as Technical Engineer. Your supervisor has requested you to construct a report as part of your training. You are required to provide a sound explanation of the theory and calculate specific parameters related to thermodynamic systems and heat transfer. TASK 1 The fundamental concepts, principles and definitions in terms of heat and work are essential for your work, as such you are required to complete the following tasks: 1. Define and explain the following concepts. Use equations and diagrams to supplement your answer: a. Phases of Matter b. Phase Change c. Latent heat of Fusion & of Vaporisation 2. In order to produce liquid water at 40oC, we are mixing a certain amount of water at 85oC with 150 g of ice at –10oC, assuming there is no heat exchange with the surroundings what should be the mass of the water at 85oC Consider: Cwater = 4.186 KJ/(kg Co); Cice = 2000 KJ/(kg Co), Lf = 335 KJ/kg; Lv = 2260KJ/kg 3. Two taps fill the water tank with different flow rates. Tap A fills the tank in 1 hour and tap B fills the tank in 3 hour If we open two taps together, find the final temperature of the water in the tank. 1 a) The graph given below shows the relation between given heat and change in the temperatures of the three matters having same masses. Compare the specific heat capacities of these matters. TASK 2 Gas laws help us understand the properties of a working fluid when it goes through certain changes within a thermodynamic system. a) Your next task is to define and explain the ideal gas processes I.e. Isochoric, Isobaric, Isothermal and Adiabatic. Use equations and diagrams to supplement your answer. b) Three containers A, B & C are having the same volume of 1 L, Temperature of 25 °C and Pressure of 101.3KPa. Container A contains (CH4); Container B (CO2) and Container C (NH3). Find the container having the highest number of moles without calculation and Explain. c) A container with the following dimensions (1.5 m x 1.5 m x 0.5 m) is filled with 1 L of liquid nitrogen. The container is completely full, the temperature is 30 °C, and the atmospheric pressure is 1 atm. If all the liquid nitrogen evaporates it will displace a certain volume of air. Calculate the volume displaced in percentage. Consider the density of Liquid Nitrogen as 0.807 g/mL and molar mass of Nitrogen is 28.014 g/mol d) A gas weighing 5 kg expands within a flexible container as per the following rule PV1.3=constant. The gas was initially at a pressure of 1 MPa and volume of 2 m3 after the expansion the final pressure decreased 5 kPa. Calculate the final volume 2 TASK 3 Your supervisor further asks you to apply the laws of thermodynamics in the following tasks: a) Explain the second law of thermodynamics, in particular how it applies to heat engine and reverse heat engine. Use equations and diagrams to supplement your answer e) The heat is supplied to an ideal heat engine from boiling water reservoir (1000C) and rejected to the atmosphere how does the efficiency of the heat engine change between a cold day (00C) and a hot day (400C) f) A heat pump which is driven by a heat engine are both rejecting heat to the same reservoir. The heat engine is having an efficiency of 25% and the COP of the heat pump is 3. Find the ratio of the total heat rejection rate to the heat transfer to the heat engine. g) Air at 15°C and 60 kPa enters the diffuser of a jet engine steadily with a velocity of 200 m/s. The inlet area of the diffuser is 0.4 m2. The air leaves the diffuser with a velocity that is very small compared with the inlet velocity. Determine: a. the mass flow rate of the air b. the temperature of the air leaving the diffuser. TASK 4 The concept of heat transfer is important to engineers to understand and analyse heat transfer rates across buildings and materials. a) Define and explain the following terms: i. Absorptivity ii. Black body iii. Emissivity iv. Grey body. b) One end of an iron poker is placed in a fire where the temperature is 450 oC, and the other end is kept at a temperature of 24 oC. The poker is 1.2 m long and has a radius of 5 mm. Ignoring the heat lost in convection along the length of the poker, find the amount of heat conducted from one end of the poker to the other in 5 s. The thermal conductivity of the iron is 79 W/mK 3 c) Two identical rectangular rods of metal are welded end to end in 2 different positions as shown in below figure (a), and figure (b). Explain how the heat will flow through the material in both cases and which case will allow faster heat transfer d) A steel pipe 140 mm inside diameter has a wall 15 mm thick. It is covered with insulation 20mm thick. The thermal conductivity of steel is 60 W/m K and for the insulation 0.5 W/ m K. The pipe carries steam at 250°C and the outer temperature of the insulation is10°C. The convection heat transfer coefficient between the steel and the steam is 200 W/m2 K. i. ii. Determine the heat loss per unit length. Calculate the outer surface temperature of the pipe END 4
Collepals.com Plagiarism Free Papers
Are you looking for custom essay writing service or even dissertation writing services? Just request for our write my paper service, and we'll match you with the best essay writer in your subject! With an exceptional team of professional academic experts in a wide range of subjects, we can guarantee you an unrivaled quality of custom-written papers.
Get ZERO PLAGIARISM, HUMAN WRITTEN ESSAYS
Why Hire Collepals.com writers to do your paper?
Quality- We are experienced and have access to ample research materials.
We write plagiarism Free Content
Confidential- We never share or sell your personal information to third parties.
Support-Chat with us today! We are always waiting to answer all your questions.
