thermodynamics

  1. C

    Leidenfrost effect and volume of water

    I conducted an experiment at school where I changed the volume of water and looked at the time taken for the water to fully evaporate, whilst undergoing the Leidenfrost effect. I'm trying to write up the theory behind it, but I keep getting confused with the terms. There seems to be so many...
  2. D

    Thermodynamics 2 - cogeneration help

    Hello, I am in my senior year of Engineering school and am taking Energy Conversion(Thermo 2). I am confused about the quality "x" values and the "s" values. I do not understand these concepts and when to apply them to get "h in the states. I am doing cogeneration examples. Also I did take...
  3. K

    Help needed for thermodynamics questions

    Finding the correct 'Length' of a pipe? Hello again, i've been struggling with question a) for a few days now and I have now reached a cross-road. The problem in itself lays in the framing of the question. So if you would take a look at the question in the attached document you will see that my...
  4. M

    First Law of Thermodynamics

    I read from a famous text-book : "when mechanical work is done on a system of gas, the internal energy of the system increases." According to the formula of the First Law of Thermodynamics,it sounds true. But ,theoretically, when we do work on a gas , it compresses,i.e.,its volume...
  5. B

    Thermodynamics

    Need a little help please. I've got a question asking work out thermal transfer and work done using Charles Law when final temp is 250k where P = ( v - 4 )^2. 5kg gas expands from 300 to 400mm^3. Cp = 1005j/kg K. Its the P = ( v - 4)^2 bit that is throwing me. Thanks for any help
  6. A

    How does Thermodynamics relate to Cosmology?

    Hi, I get a lot of classical thermo e.g. concepts of pressure, temperature and entropy in a closed control volume, but I don't exactly get how it's applied to big picture things such as galaxies, nebula, black hole and the beginning of the universe. I really can't conceptualise anything that...
  7. S

    Qick Thermodynamics Quiz

    A small block is placed in a smooth bowl and held partway up the side of the bowl and then released, whereupon it slides down towards the bottom. Discuss the system and How much work is done?
  8. R

    Thermodynamics problem

    An industrial boiler is fitted with a sight‐glass device to indicate its level of liquid and the boiler contains saturated steam at 200°C. During the routine "blowdown" procedure, liquid water is purged from the bottom (mud-drum) at a slow rate, and the temperature in the boiler remains constant...
  9. E

    problem in thermodynamics

    Hi I am solving a problem. I have water in a piston cylinder arrangement. the water is at 150 deg C and has a volume of 24 m3. the mass of water is 25 kg. I need to find the pressure of water at this state. I am confused... how can I find it. one more thing this water is compressed accroding...
  10. S

    Thermodynamics - Temperature change of argon gas

    the temperature of n = 19 mol of argon gas is increased from T1 = 21 oC by Q = 4.4 kJ heat transfer, while the gas pressure is kept constant. What is the new gas temperature in Celsius degrees? Q=n*Cv*change in Temp as its a monoatomic gas I think this means that the equation is just...
  11. B

    Lengthy Thermodynamics Cycle Problem

    I know I must have already attempted to solve this problem, but I am overwhelmed with finals so I'd be happy to PayPal someone to complete this problem. Please, please help. My email is vodkamakesmesober@yahoo.com, email me if you are willing to help! Thank you. You design custom...
  12. D

    Help needed for thermo efficiency

    Still working on my physics nearly done, I need help with the calculations of heat transfer in a room of 10x10x5high in metres, with the use of heat pump, and gas furnace. The purpose of the calculation is to determine thermal efficiency ..plus energy required to heat the room from 0 to 25 C, I...
  13. D

    Greetings all

    Hi everyone, I am currently seeking help for one of my assignments involving the topic of thermodynamics in domestic heating. I will be comparing the gas furnace and AC heater for benefits, advantages and vice versa. Does anyone have any suggestions on how or what I should do to calculate the...
  14. avito009

    Jigsaw puzzle and second law of thermodynamics.

    I have read that when you decrease entropy somewhere it has to increase elsewhere. So when you put a jigsaw puzzle in order this decreases entropy of the puzzle but it should increase entropy elsewhere but where? When you decrease the entropy of a system it should increase elsewhere but where...
  15. Z

    Saturated mixture expansion thermodynamics

    A vessel is containing a saturated mixture of 1kg liquid water and 100g steam at 100 degrees celcius. The vessel is connected to another container with the exact same volume, and the mixture expands freely so it fills the doubled volume. The system is thermally isolated. What is the final...
  16. W

    Thermodynamics

    I have a question guys: (Smile) Question: 10 kg of R-134a fill a 1.348m^3 rigid container at an initial temperature of -40 degrees. The container is then heated until the pressure is 200 KPa. Determine the final temperature and initial pressure. OK! I have tried everything, but I just...
  17. T

    Physical significance of PV of a gas mass

    Hi This might seem to be a simple question off the bat, but I would like your comments on it. When pressure of a gas is P and specific volume is v what is the physical meaning of Pv? I tried to interpret it as the "Compressive Energy" of the gas mass. Assume the air mass is at the volume...
  18. O

    Mass flow rate of water in a hydraulic turbine

    Hello again. I have another problem that I'm working on: The intake to a hydraulic turbine installed in a dam is located at an elevation of 10 m above the turbine exit. Water enters at 20 C with negligible velocity and exits from the turbine at 10 m/s. The water passes through the turbine...
  19. O

    Energy being transferred to a container with air...

    Hello All. I would appreciate any help you can offer on this problem! Air is tightly contained in a closed, well-insulated tank with a volume of 0.5 m3. The tank is fitted with a paddle wheel that transfers energy to the air at a constant rate of 3 W for 1 hour. The initial density of the...
  20. G

    experimental thermodynamics properties

    Hello everybody, I am using an equation of state to calculate the thermodynamical properties of a material. I have a problem which is the ideal part of the equation. Actually, I cannot be sure that the ideal contribution in my equation is the really ideal contribution, so I decided to calculate...