transfer

  1. E

    Water-air heat transfer

    Experiment: The air currents of two large domestic fans were directed toward the water surface of a 50-gallon tank while the ambient temperature was 88°F. If at the beginning of the experiment the water was at 77°F, why did this temperature drop? Shouldn't it have been the other way around...
  2. J

    Water Heater - useful energy content

    Hi, i´m developing a project and have some questions about thermodynamics I have this table with data. And this is what variables are: -useful water flow rate (f) means the minimum flow rate, expressed in litres per minute, -useful water temperature (Tm), means the water temperature...
  3. J

    Accelerated heat transfer test

    Hi everyone! I want to keep a pharma product between 2-8°C for 48 hrs in a 30°C ambient using an insulated box with ice packs in it. If I want to reduce my test time to 8 hrs, by how much should I raise the testing ambient temperature to get valid results as if it was a 48 hr 30°C test? As...
  4. R

    Heat transfer between flue gas and feed water?

    I need to determine the temperature of flue gas in a fire tube boiler. Tube inlet gas temperature, T1 = 1045 deg.C Saturation water temperature, tsat = 186 deg.C Flue gas temperature, t2 = ? 2 equations to be used here: Q = U.A.LMTD -------------(1) Qg = Mg.Cg.(T1 - T2) ------(2)...
  5. E

    Heat transfer between 3 bodies

    Hi i have problem i want to solve that is related to an industry. The problem is that i have 3 rectangular wood plates. The middle plate starts with 120c degrees. The upper and lower plate are being constantly cooled so they keep a temperature of 20 degrees celsius all the time. The question i...
  6. F

    Heat Transfer

    Please help clarify which is the correct answer and or method to the following problem: Ideally, when a thermometer is used to measure the temperature of an object, the temperature of the object itself should not change. However, if a significant amount of heat flows from the object to the...
  7. R

    Heat Transfer

    Hello, all. I'm a newbie in physics and am looking to pursue mechanical engineering as a degree. Thermodynamics is very interesting, but I'm stumped on a question without any way to test it out. This isn't for school, but rather for my own studies. Does the presence of heat in a conductor...
  8. D

    Heat Transfer between 2 control Volumes

    Hey I'm new to the forums, but I could really use some help with a problem. My school does a senior design project where we design and build some prototype system. My team has a client that wants an internal cooling device through inhalation. I'm the only team member who has had experience with...
  9. P

    Film condensation heat transfer coefficient on helical tube

    Hi guys, I am working on my final year project and struggling to calculate the film condensation heat transfer coefficient on the my condenser. All I could find was the heat transfer coefficient on both vertical and horizontal plates and tubes. I can't seem to find h for helical tube that is...
  10. P

    Condensation heat transfer coefficient on helical condenser

    Hi guys, I am working on my final year project and struggling to calculate the film condensation heat transfer coefficient on the my condenser. All I could find was the heat transfer coefficient on both vertical and horizontal plates and tubes. I can't seem to find h for helical tube that is...
  11. S

    Maximize heat transfer in ductwork

    Yes, you read that right. In contrast to the typical goal with ductwork, I'm trying to MAXIMIZE the amount of thermal energy transferred from the air inside the ducts to the surrounding environment. Here's the situation: I have roughly 12 feet of distance to cover with a 4" diameter duct. One...
  12. C

    Integration of heat transfer rate equation

    Hi everyone, I am trying to do an analysis of a steam pipeline to compare the use of steam to warm up a pipeline after shutdown versus other methods (heat strips). The one thing I am trying to figure out is the units for the integration of the heat transfer rate equation which is...
  13. G

    Heat transfer in molten metals

    Hi all, I am currently working on a heat transfer problem for a galvanizing process. I would like to determine the time it takes wire to saturate to the temperature of the molten lead it is pulled through. The problem I have is in calculating the heat transfer coefficient h. The wire is...
  14. R

    Heat transfer in double pane window

    You need to design a double plane window that is comprised of two 5mm thick slabs of window glass (mean thermal conductivity 0.84 W/(mk)) with a gap of stagnant air (mean thermal conductivity 0.02W/(mk)) in between them. The room temperature is 298k, outside temperature is -15c. The heat...
  15. V

    Step response and peak response of a transfer function Reference https://www.physic

    1. The problem statement, all variables and given/known data The open loop transfer function to a unity negative feedback system is given as: G(s)=50/s(s+10) 2. Relevant equations Unity feedback is used in this problem, and the system input is a step function. Y(s)=50/s(s^2+10s+50) 3. The...
  16. V

    heat transfer in atmosphere

    A cirrus uncinus cloud (a hook-like cloud appearing at an altitude between 5 to 15 km and indicating a slowly approaching storm) has an average thickness l=1000m The extinction coefficient for the cloud is sigma 2.2*10^-3 The intensity of the irradiation at the top of the cloud is 830w/m^2...
  17. V

    heat transfer in atmosphere

    A certain smoggy atmosphere has a turbidity factor 4 n . Calculate how the direct, cloudless sky insolation varies with the Sun altitude angle? How much is this reduced from that of a clear sky? thanks in advance, awaiting for positive reply!!
  18. V

    Heat transfer in atmosphere

    A cirrus uncinus cloud (a hook-like cloud appearing at an altitude between 5 to 15 km and indicating a slowly approaching storm) has an average thickness L 1000m . The extinction coefficient for the cloud is 3 -1 2.2 10 m     e . The intensity of the irradiation at the top of...
  19. H

    Heat Transfer Application examples of using fins

    Hello, Im struggling a bit with this problem. I dont know how to sketch the equivalent thermal circuit for any of them. Does it have to look like anything like that? the thermal circuits are for b) parallel connectd right? and for aswell? And im getting wrong answers for a). Shouldnt...
  20. H

    Heat Transfer

    Hi, so i have to design a system whereby steam is generated in a pipe from the use of a heater/parabolic mirror. I have water coming in at 15 degrees and steam leaving at 100 degrees, i know the heat flux coming in and i am allowed to change the specifications of the pipe. However, when i...