Heat transfer Definition and 947 Threads

Hello, all, I am currently trying to solve a problem at my internship concerning the heat transfer analysis of a Grade-2 titanium rod. The Ti rod is placed in an environment of 300 degrees C, and I am trying to solve the problem of the steady-state temperature of the Ti capsule. The length of...

1. My first hypothesis is that the thermal conditions of a ground source heat pump (GSHP) ground loop never reach steady state because the thermal mass of the surrounding soil is large enough that the time constant for temperature gradients moving away from the pipe before reaching boundary...

Cooling Lerasium to its melting point: Q1 =m L⋅c L,liquid ⋅(T L,i −T L,melt) Q1 = 1.49kg⋅221.6J/kgK⋅(1108.1−56.4)K Q1 = 330.184 ⋅(1051.7) = 347254.512 J Heating Atium to its melting point: Q2 =mA⋅cA,solid ⋅(TA,melt −TA,i) Q2 = 2.44kg⋅524.8J/kgK⋅(308−33.6)K Q2 = 1280.512⋅(274.4) = 351372.493 J...

Hello, I have some doubt on the representation of the physical model. I'm not sure about the number and value of the capacitance to be used. I solved the exercise using this model (see figure) and i would like to know if the solution is correct or if there is something to fix. Regarding the...

Dear all, I am having some difficulties in generating some heat conduction curves. My problem is: I have an object at a temperature (Th) of 900 K placed on top of a surface with a temperature (Ta) of 300 K (see Figure). The thermal conductivity (K; W M-1 K-1) is 1.5 whilst the thermal...

Currently, I am working on a project that necessitates a quantitative risk assessment (frequency analysis and consequence analysis) of buried crude oil pipelines, considering specific hazard scenarios. Most of the hazard analyses I have come across were conducted on gas pipelines, and there...

If aluminum foil were used to help conduct heat with pine and sheet rock (0.14 W▪m/m2▪°C and 0.43 W▪m/m2▪°C respectively) would it also help conductivity for glass and plexiglass (0.86 W▪m/m2▪°C and 0.19 W▪m/m2▪°C respectively)? When does the transition of insulator and conductor happen for...

This problem is created by my cousin who is learning about 1-D heat transfer problems. He made this problem and made solve it with fourier's law of heat transfer with calculating thermal resistance by integrating 1/A dx, which presupposes a false assumption; if the distance away from the heat...

Does this working out look okay? Thanks in advance.

Considering the approximation of perfect gas, I don't understand why at higher altitude the temperature is lower. Intuitively it is clear to me, but I do not understand the kind of transformation that takes place; the gas is free to expand and the pressure too is not constant, since it decreases...

Hello all , I need to estimate the time it would take for the inside of a hollow cylinder to reach a limit temperature (detailed data below), in order to adjust the wall thickness and choose an insulating material to delay heating as much as possible. Being a total beginner in thermodynamics, I...

A typical UK domestic hot water tank holds c. 200 litres of water. Hitherto the common method of heating it to say 60C has been by means of an internal coil of copper pipe through which is pumped hot water from a gas boiler at ~ 70C. Heat transfer on the outside of the coil is by natural...

Referring to the attached, the bottom right is an electronics compartment. The external panels are 20GA steel powder coated yellow. There is 1-inch of R-6 foam board insulation on the inside of all external walls. The skid is exposed to ambient heat and direct sunlight when on site. If we...

I am constantly research a wide range of areas and often run into questions I cant seem to find the answer to, no matter how much I ask uncle google. I am looking for open dialog and discussion, so I dont mind getting off topic a bit. I like the inspiration. Tho periodically I may need a...

Say I have a real counter flow heat exchanger using air and water. I run a test so I know every parameter; mass flow rate of both fluids, surface area, and in and out temps. This is great. Now I can calculate the heat transfer rate, my log mean temperature difference, and overall heat...

I have a cube with a volume of 1000m3 at an initial temp of 290K. The bottom side (10m by 10m) is open to the ambient air. I put this cube into a huge fridge and cool the whole volume by 5K. I close the open side by placing a cover on it. This cube has now got a volume of air at a temperature of...

Hi, zero education on heat transfer here, need some help. I have an electronics module that generates 15 W of electrical power over a 70mm x 20mm x 15mm heat load volume (aluminum). The ambient temperature is 25° C, the maximum temperature the heat sink can be is 40° C (ΔT = 15° C). Does...

Looking to build a suitable closed loop water (probably glycol mix) circulation system to prevent livestock water troughs from freezing. I assume that I need to calculate how much heat loss is predicted from the water tank in ambient air (varies, but assume worst case), then what length of heat...

Hello everyone, I'm trying to solve the transient heat transfer problem within the ID wall. The material is steel, and it is isotropic. The properties are given below : L = 5 mm qin = 0 Tinf = 100 deg C Tini = 20 deg C rho = 7850 kg/m3 cp = 460 W/Kg.K k = 45.8 W/m.K h = 20 W/m^2.K alpha = k /...

I'm using a stainless steel pan and a fan to cool my coffee down as quickly as possible. Usually, I have the fan blowing down towards the coffee, but this morning I flipped it over to suck the heat out of the coffee and I'm wondering which of the two is the most efficient, especially as, in the...

I have some doubts about a thermodynamics exercise I did-I'll write down the text and show how I tried to solve it to see if I reasoned it out right. In a container of thermal capacity ##C## containing ##1.0 kg## of ice at a temperature of ##-4.0 °C##, a mass of ##3.0 kg## of water is poured...

Hello, I'm looking over some old school notes and re-learning some basic heat transfer. I have known Fourier's Law (1D: ##q = k\frac{dT}{dx}##) for a long time, but when I look at it now I find it strange that heat flux is inversely proportional to the length of the conductor. I would think...

Apologies, made a mistake when posting. Please see below post.

I have a solar water heater on my deck, with a circulator powered by PV, that pumps heated glycol through a wand heat exchanger placed in an 80 gallon tank. Water comes from the well's pressure tank, passes through this solar pre-heater tank, then into an LPG heater that adds any heat needed. I...

Hi, cannot get a definite answer anywhere on how heat transfer occurs with this fluid. All that the manufacturer gives is "excellent heat transfer". Water has excellent heat transfer due to convection currents. Need to know if this fluid also heats by convection rather than conduction...

***A Carnot Engine*** is a theoretical engine unlike a Sterling Engine which can be made practically. Some of the drawbacks of Carnot Engine are, 1)The Heat Transfer occurs only during isothermal process(compression and expansion),this is because the working material (ie) gas or fuel used, if...

So far I have determined the evacuation time, a basic heat transfer between the heating element and plastic sheet, and a hold down force of the forming bed.

Hi, I'm trying to solve a problem involving radiation in a triangular cavity: As you can see, lengths and emissivities of all surfaces are given. For two of them, the heat flux is known and the temperature has to be found while for the remaining surface it's the other way around. I have the...

Hi guys, I'm a 2nd year mechanical student currently taking heat and mass transfer. A question came up in my mind when I was looking into the conduction heat transfer. If I put block B on block A where block A is 573K and block B is 303K. Is there any way that I can calculate the time required...

I have been given the task of modeling the heat transfer from a light source of known power into a system consisting of two connected materials. I must find the temperature change in the bottom surface. The two materials are initially in thermal equilibrium with the surroundings. My first...

I believe that just using the equation above should yield the following: R_{tot} = \frac{18 -(-5)}{400 + 2(80)} = 0.041 but the units don't seem to match up... The units of the above answer are in K / W. Is there a different formula i should be using? Your help is appreciated!

Hello ! My name is Amine, Renewable Energies Student (Thermal Conversion Masters degree) . interested in numerical analysis and applied mathematics . Currently focusing on Heat and Mass Transfer , Fluid Mechanics and Matlab programming. ready to efficiently help on those subjects please...

Hello everybody, would somebody please put me on the right track to answering this question? 'Consider water undergoes a heat transfer at constant pressure of 10 MPa and changes from liquid to steam. Find the entropy of the system (sfg) as well as the heat transfer per unit mass in this...

The question & my solution

Hi, I've checked the literature but couldn't find any formulas or examples for this particular problem involving heat sink with straight fins: As you can see, I want to assume: - power at the bottom surface - convection (known ambient temperature and heat transfer coefficient) at the...

Hi, starting for this thread Question about entropy change in a reservoir consider the spontaneous irreversible process of heat transfer from a source ##A## at temperature ##T_h## to another source ##B## at temperature ##T_c## (##T_h > T_c##). The thermodynamic 'system' is defined from sources...

What is the difference between the approaches of Einstein, Debye and Peierls regarding the heat transfer?!

In general, in the paper Casimir assumes that between the boundaries of a crystal the heat transfer can be imagined as electromagnetic radiation between two hollow bodies connected by a tube (at least this what I understood from his approach), I'm reading about Casimir limit (Ballistic heat...

Let's say we have a cylindrical fuel pin with fissile material in the middle, followed by a gas gap and cladding material. It is being cooled by water on the outside. The temperature drop through the fissile material should be parabolic due to heat generation, and the temperature drops through...

Hi Everyone, I am looking to find how much heat can be stored in a concrete pipe of roughly 0.3-0.4m diameter, and an internal diameter of 0.05m. Air will travel through the internal diameter at 500°C and 17.5bar which will provide the heat for the pipes. This system will then be reversed so...

Summary:: How to calculate the rate of heat transfer between hot external water and cold internal water in a pipe. The image attached is my attempt at the question however, I find myself stuck trying to work out internal and external heat transfer coefficient.

Hey guys! This is problem from Callens Thermodynamics textbook and I'm stuck with it. My goal was to get a expression for the entropy ##S## which is dependent on ##T## so I can move into the ##T-S##-plane to do my calculations: I startet by expressing the fundamental equation as a function of...

A steel pipe with foam insulation is embedded in a concrete wall. The steel pipe is carrying cold water and therefore gains heat from outside atmosphere. Heat transfers through the concrete wall, foam insulation and then to the pipe. Is it possible to calculate critical radius of insulation for...

My experiment procedure is that I am using burning charcoal as the heat source, and there are three thermocouples used, first one measuring the temperature of the charcoal, second one measuring the inner temperature of the concrete block, third thermocouple is placed on the top part which is...

So firstly, I don't understand if the mass flow rate is for steam or for water. If it is for water, I know I can find the heat transfer rate using equation:Q=mcdeltaT. But then I don't know how to find h (the average heat transfer coefficient) because I don't know the surface area (As). I can...

Hi, I am trying to understand how I can estimate the time it takes for a fluid at room temperature flowing through a thin capillary glass tube (2 mm ID) connected to an oven to reach the equilibrium temperature (oven temperature). Assuming the oven is preheated and the tube inside the oven is...

Basically this would be a closed loop geothermal system for electrical power generation. The system would consist of 2 Horizontal Wells connected creating a U-shaped closed loop cycle using thermosiphon effect, with constant recirculation. It's not really a conventional geothermal power...

Im practicing the questions in the problem book and seem to be getting different answers to the book can somebody check cheers. [Answers: 57.99 W/m: 1739.7 W: 84.9ºC] textbook answers A water pipe of bore 65 mm bore and 6mm wall thickness, carrying water at 85ºC is insulated with one layer of...

Please could someone point me in the direction of an equation/ book I can use to obtain the convection coefficient for steam in a heating jacket. Steam is at 1 bar pressure. I think I need to use a dimensionless number. Thanks

A water cooled plate condenser, condensing refrigerant. Heat exchanger (condenser with plates) characteristics: Description symbol value value (converted) number of plates np 28 number of channels nc 27 number of water channels nwc 14 number of flowing channels for refrigerant...