Hi,
when modeling convective cooling in FEA one needs to define film coefficient ##h## and ambient temperature ##T_{amb}##. The software calculates convective heat flux using this data and current surface temperature ##T_s##: $$q=h(T_{s}-T_{amb})$$ However, modeling of moving cooling nozzle may...
Assume there is a boundary seperates two medium with different heat conductivity [κ][/1] and [κ][/2]. In one medium, the temperature distribution is [T][/1](r,θ,φ) and on the other medium is [T][/2](r,θ,φ). What is the relationship between [T][/1] and [T][/2] ?
Is it - [κ][/1]grad [T][/1]=-...
Hello,
I'm looking for the governing equations for the laser radiation on a surface. I understand there are several types and methods. I was wondering if there is an equation to show all the parameters in calculating a surface temperature after laser radiation for a specific time. Some of the...
Hey guys.
I have a room which i want to use as a server room. the devices need to work 24/7 and they get pretty hot. so it is imperative to keep the room cool otherwise the devices will be damaged.
I have an air vent to bring cold air into the room for the devices so their fans can suck in cold...
Hello,
I am a Mechanical Engineer a little out of practice on Heat transfer. I am trying to solve this problem. It must be solvable but i have yet to find right equations online.
I have a multi Layer Cylinder made up of C350 marraging Steel,Zinc Alloy-12 , then 6061 Aluminum T6. All that is...
I am trying to determine the size of a single cartridge heater or 2 cartridge heaters to heat a large mass of aluminum to 400F. The aluminum block will be sitting inside an insulated (all sides) enclosure. The following are the specs for this problem.
- Max surface temp of aluminum block is...
I'm trying to find a heat transfer equation that includes time. Metal tank, partially filled with liquid. I need to find the time it would take for the temperature on the outside of the tank to drop from θ2 to θ1, given thickness, metal and liquid's properties, and tank dimensions
I tried modeling the problem quite a few ways. one was to say that the difference between the heat emitted by the room and the heat emitted by the bulbs would equal the heat absorbed by the room, and that could allow us to calculate temperature. This did not work. I'd appreciate your help
I worked on a lab experiment that was meant to measure heat capacity but left me with some other questions. The students measured the mass of a cup of liquid nitrogen as it boiled off, recording mass vs time. Then they drop a solid object into the bath, one experiment with a small bit iron...
I am working on a project to dry liquid digestates (residue from the fermentation process of biogas plants).
The liquid digestate has a dry matter (DM) content of about 3%. The digestate is primarily made up of animal manure and maize silage. It is a non-newtonian fluid having a viscosity of 4...
Heat transfer: Conduction - Convection - Radiation, but I was wondering if conductive transfer is actually radiation transfer, but at contact distances; well not really contact since no material actually touches each other (at a quantum level).
So, is conductive heat actually being...
I am currently trying to solve a problem for my dissertation. Help would be greatly appreciated. :)
A silicon solar panel of area 1m^2 is being warmed by the sun. It achieves a constant temperature of 80 degrees celcius.
I am trying to cool this panel which is constantly being provided solar...
I have an interest in storing, for later use, energy from excess shaft power developed by a wind turbine. Currently I am assuming that the compressor is running in a steady fashion, continually drawing 300K, 1.0 atm. air into the compression chamber and compressing it to 20 atms. before...
I'm having trouble verifying an experiment I ran to determine the power dissipation of a heating element. 13.15W of power was applied to 3ft nichrome wire. Temperature readings were collected until they stabilized at 128.5F (room temp was 70F). I want to create a mathematical model of the system...
Homework Statement
A double effect forward feed evaporator is to concentrate a 12.5% solution of a certain chemical compound "YZ". The feed is to be at and is to be 120 F of such an amount as to contain 6250 "YZ" per hour. Saturated steam is available at 250 F (29.7 psi ). The accepted value of...
Here is a fun question for you heat transfer experts.
I have a high pressure waterjet firing into a open tank of water. The hydraulic power of the jet entering the tank is known, along with the flow rate of the jet entering into the tank. All of the energy of the jet is dissipated into the...
Homework Statement
In a frictionless piston-cylinder system, there are 3 kg of R-134a initially at 280 kPa and 15 °C. Heat is transferred to the system in the amount 120 kJ. What will the final temperature of the refrigerant be (deg C)?
Homework Equations
Q - W = ΔU (internal energy)
Q - Wb...
In my heat transfer course, I always had to do analysis of long-wavelength radiation between surfaces first, and find the heat radiated from one of the surface. Then, solar radiation is added to the problem, and suddenly it was said that solar radiation=heat radiated from this surface! Does...
Homework Statement
n moles of gas, that follow van der Waals equation are to be employed as the auxiliary system in a circular cycle(parameterized using T_h and T_c as shown on the TS diagram. Calculate the efficiency of the cycle.
Homework Equations
, , Q = TdS
The Attempt at a Solution...
My book states that
Heat and work represent energy in transit. The state of the system undergoes a change after heat is supplied to it and before work is extracted from it because energy gets stored in it.
My doubt is here that ,heat has been transferred to the system and it says heat is energy...
Hi there,
Hopefully this is a very easy question and you all can just confirm this for me.
When calculating heat transfer into a fluid from a heated tube, is it correct to say that the heat transfer coefficient is *not* dependent on the tube diameter?
So, if we solve for T_{out}, we get...
Hello, i'm currently taking some summer classes at my college and was assigned a project to transport vaccines from one location to another (travel time ~2-5 hours.) We have to keep the vaccine within the range of 35-46 degrees Fahrenheit at all times. My group and I came up with the idea of...
My book states that when a flow around object is considered,
Non dimensional momentum flux is defined as the drag coefficient
In case of flow through tubes it states
The non dimensional momentum flux is defined as the friction factor
What do these statements mean? What do they practically...
Homework Statement
A 5m long heated pipe is used heat up water from 15°C to 65°C. Water flow through the pipe is 10liter/min. The heating gives a constant heat flow in all parts of the pipes surface. The inner and outer diameter of the pipe is 30 and 50 mm, respectively. Calculate the heat...
Homework Statement
I am confused on how it's using the surrounding temperature minus the surface temperature as its the other way around in the Newton's law of cooling, Doing that would change the sign of convection right? I dont see the reason to do that, since if left side is hotter, then...
Homework Statement
One end of a solid cylindrical copper rod 0.200 m long and 0.0250 m in radius is inserted into a large block of solid hydrogen at its melting temperature, 13.84 K. The other end is blackened and exposed to thermal radiation from surrounding walls at 500.0 K. (Some telescopes...
Homework Statement
I dont understand the derivation of the right side of the last equation.
Homework Equations
The Attempt at a Solution
I got to this point, I also dont understand why it did not include C_2 for the variation of temp. along the fin.
I am guessing the right side is the...
Homework Statement
Homework Equations
The Attempt at a Solution
I thought it would become d/dx(-kAc*dT/dx)+hp(T-T)=0 instead of where the equation in the red box? I dont see how are they equivalent [/B]