Questions tagged [heat-transfer]

Questions relating to the transfer of heat via the mechanism of convection, conduction, or radiation, in forms of systems (or your device) attempting to obtain thermodynamic equilibrium with another system (the environment or your other device)

Filter by
Sorted by
Tagged with
1
vote
1answer
27 views

What material might by used to 'staple' coils down in this stovetop element?

I have the stovetop element shown in the image below. If you look at the coils, they're fixed down by what look like little staples. I'm wondering what material those staples might be. The surface ...
0
votes
0answers
19 views

how to obtain solution of this bessel equation using Frobenius method

Given this equation: $$ \frac{1}{r}\frac{d}{dr}\bigg(r \frac{dT}{dr} \bigg) - \bigg(\frac{2h}{bk} \bigg)(T-T_a) = 0 $$ I can let $x=r\sqrt{(2h/bk)}$ and $z=T-T_a$ to obtain the bessel equation using ...
1
vote
0answers
14 views

Passively Controlled Heat Exchanger

I am currently working on designing a heat exchanger that "passively" controls temperature. Just for a little bit of context: By passive, I want to limit any use of regulating valves, ...
0
votes
1answer
21 views

How is heat transfer calculated for an aqueous salt solution?

I am familiar with using $\dot{Q}=c_p\cdot\dot{m}\cdot\Delta T$ to calculate the heat transfer rate of a fluid given a singular value for specific heat capacity (such as with water), but how do I go ...
1
vote
0answers
31 views

Increase in internal energy and temperature

A banquet hall (150 m3) is to be used for a formal dinner for 20 persons. Each person occupies 0.075 m3 of space and has an average heat transfer rate of 500 kJ/hr. If the AC system fails, determine ...
1
vote
2answers
61 views

Does venturi effect helps in reducing temperature of a room?

I clearly didn't understand how this works, but the explanation and claim that it reduce the temperature of room by 5°c made me wonder, here I am trying to understand the Venturi-effect on temperature ...
1
vote
1answer
47 views

Determining the final surface temperature and final gas temperature flow through a tube in a room

I am trying to calculate the final temperatures as stated above. There is hot gas flowing through a tube that is insulated and inside of a room (no wind). I will try to walk you through my thought ...
1
vote
1answer
42 views

What's the setpoint of the temperature on the primary side of a heat exchanger?

I have a heat exchanger with known flows on priamry and secondary sides - $\dot m_p$, $\dot m_s$, known temperature in $t_{si}$ and a desired temperature out on the secondary side $t_{so}$. How to ...
1
vote
2answers
43 views

Disc Brakes - Swept Area , why is larger better?

I am trying to understand why a bigger swept area on disc brakes provides higher braking force for the same force being exerted on the brake lever/pedal by the rider. If we use the same exact brake ...
0
votes
0answers
61 views

Setting up a radiation heat transfer problem

I am trying to solve a radiation heat transfer problem. The problem is set up like this: Two spherical shells of radius R whose surfaces are separated by a distance R. One shell, call it A, has a ...
1
vote
1answer
32 views

Is there any unilateral heat exchanger?

I don't know if this is even possible or not but are there any pads that can transfer/exchange heat from one side to the other side unilaterally? I mean that the heat could be transferred from one ...
-1
votes
1answer
33 views

How much time to melt marshmallow under heat lamp?

Using the Specific Heat Formula, I found that I need to apply 612J of heat to melt 18g of marshmallow. Marshmallow has a specific heat of 2 J/(g*C), melting point of 98.6°F, and a starting room ...
1
vote
3answers
31 views

Material selection of heating element

I am interested in heating coils which are heated using Ohmic/Joule/resistive heating - specifically, how the material for the heating coil is selected. When I read about heating coil materials - ...
-1
votes
1answer
36 views

As a rugged and waterproof device, how does gopro dissipate heat?

I am new to designing rugged + waterproof products. I am curious about how to dissipate heat when the electronics are running and the ambient environment is even hotter. It seems like the mode of heat ...
1
vote
1answer
23 views

If you have a small fan that blows hot air, and a larger fan that blows cold air against it, what happens to the hot air?

For context, I have a laptop that has a fan that sucks in cold air from the top on the left side (for cooling the cpu), and a fan that blows hot air out the bottom on the right side (for cooling the ...
0
votes
2answers
99 views

Water Cooling a Personal Computer

I intend to water cool my next PC. There are three areas of heat production in a PC - the CPU, the GPU and the motherboard itself. Would it be more effective to treat these three areas separately (...
1
vote
2answers
37 views

Can wet welding be done in mineral oil?

I'm interested in knowing whether or not submerged welding can be done in fluids other than water, specifically mineral oil in this case. The reason I want to know is that I'm looking into designing ...
0
votes
2answers
34 views

When is a heat exchanger worth it?

I am currently working on a huge industrial process for a student project and we need to transfer around 25MW of energy between dozens and dozens of streams, some larger and some smaller ones. Many ...
1
vote
2answers
57 views

Most efficient orientation of exhaust vents on top plate of chassis for air flow with regard to heatsink fins?

I'm looking for some advice from an ME or anyone who understands heat transfer,convection, etc. I'm currently laying out in Inkscape a top panel for an audio amplifier I'm building. Now, my question ...
1
vote
0answers
22 views

Heat loss calculation and Energy Balance

The image shows the CAD model of the annealing zone in a galvanization simulator. The zone is electrically heated with a AC current of 5597A at 2.09V. This whole zone is surrounded by insulating ...
2
votes
0answers
19 views

One dimensional U-Factor Calculation - How to determine indoor / outdoor film resistances

Can someone clarify the ASHRAE Fundamental 2017 (SI Units) (See Below) Indoor and Outdoor film resistances. The manual states that it comes from Table 3 and in the description of table 3 it states &...
1
vote
2answers
19 views

Diffusion Pump Copper Cooling Coil Repair

I bought a Varian VHS-4 oil diffusion pump off of ebay about a year ago. The pump was stored outside by the people I bought it from so it suffered mostly cosmetic issues. Recently I have acquired all ...
0
votes
0answers
15 views

Determining the heat capacity of an X-Band transmitter

I am conducting a thermal analysis of an X-Band transmitter that will form part of the payload in a CubeSat. The goal is to determine how long the X-Band transmitter can operate before it will ...
1
vote
0answers
8 views

Heat Conduction/Convection Along discontinuous tube

I have a question regarding heat conduction/convection. I have a metallic tube over which a rope heater is wound, supplying power. A glass tube and a 2nd metallic tube lies at the exit of the first ...
2
votes
1answer
43 views

Simulation of temperature in insulated box

I have a box outside that I want to insulate such that the temperature inside the box doesn't drop below 10°C given outside temperatures of (in the most extreme case - at night) -10°C. Inside the box ...
1
vote
2answers
58 views

How to calculate heat and mass transfer rates from an enclosed box?

I'd like to know if it's possible to calculate the heat and mass transfer rates from a small volume to the environment. Let's assume there is a box with a small opening at the top. The air inside the ...
1
vote
1answer
71 views

Safe temperature thresholds for #2 HDPE and #5 PP plastic

It would be convenient to use a temperature adjustable heat plate (element)/mug warmer for the massive amount of blender bottles accumulated over the years. What are safe thresholds to safely warm the ...
1
vote
0answers
19 views

Adding a black plastic layer to increase retained heat in compost

I have some invasive climbing weeds to break down into compost. I don't want to discard the biomass, but I do want to thoroughly kill all the weeds and ideally the seeds over a period of months. The ...
4
votes
2answers
48 views

Effects of Solar Shield on Electronics Enclosure

I am designing a prototype of an electronics package that will sit out on a pole in the sun 24/7 with a max ambient temperature of 50˚C and at 30˚N latitude. It produces 50W of internal heat ...
-1
votes
1answer
50 views

How can I calculate the airflow needed for a fan to cool a system?

The airflow needed for a system to sustain itself at 80°C with 25°C ambient temperature can be calculated with this formula: ...
1
vote
2answers
67 views

How effectively will this evaporation setup cool down the water?

I devised a setup, and I show it in the diagram below. Suppose I have these specifications: Water in the bottle is 5 liters and it's initial temperature is 28°C. The bottle capacity is 6 liters. The ...
0
votes
0answers
77 views

When does Q = m(h2 - h1) hold true?

From the first law of thermodynamics: $$\Delta U = Q_{12} - W_{12}$$ where $\Delta U = m(u_2-u_1)$, $W = p(V_2 - V_1)$ with constant pressure, and $Q = m(h_2-h_1)$. In the energy rate form of the ...
4
votes
2answers
605 views

Why Nusselt number for laminar flow in a pipe is independent of reynolds number

I understand that for fully developed flow inside a tube (with constant properties), Nusselt number doesn’t change in axial direction but it is surprising that it is also independent of Reynolds ...
5
votes
1answer
115 views

In a diesel engine, does more heat leave the engine through the tailpipe or the radiator?

Diesel exhaust is hot, and there's a lot of it. Diesel radiators also get pretty hot. In a typical diesel engine, which one is dissipating more heat? EDIT: In response to a request for specificity ...
-1
votes
1answer
23 views

Heat transfer for a copper rod

For a copper rod heated by a heat gun, why might the temperature of the rod continue to increase for a short time after the heat gun has been removed as the heat source? With reference to transient ...
2
votes
1answer
18 views

Why do plate exchangers typically serve lower pressure fluids than shell and tube heat exchanger?

According to Wikipedia http://en.wikipedia.org/wiki/Heat_exchanger, plate exchangers typically serves lower pressure fluids than shell and tube heat exchanger, why? Tubes in plate exchangers are ...
1
vote
1answer
12 views

Melt plastic powder bed with radiant heat?

I want to melt a bed of plastic powder so that the powder bed once melted and then cooled forms a solid sheet of plastic. In order to melt the powder I'm thinking of passing a nichrome (Ni80/Cr20) ...
1
vote
0answers
306 views

How does the Xbox Series X “Heat-sink chassis” work?

I understand what a heatsink does, but I cannot wrap my head around how the newly announced Xbox Series X's heat-sink chassis works. From Xbox: Heat-sink chassis A heat sink is a non-electronic, ...
4
votes
2answers
96 views

What are these outdoors “mystery boxes” for in the USA?

While watching random videos shot in the USA (in the present time), I've noticed these little weird outdoors boxes: What is the purpose of these? They look like they might be related to ventilation ...
0
votes
0answers
18 views

Simulating heat conduction on a 1-D Fin

I am trying to simulate the heat conduction on a 1-D fin. The problem I am having is that I do not know how to properly calculate the temperature in the last point of my 1-D grid. We were asked not to ...
-1
votes
1answer
61 views

Heat Transfer Problem , 1 Dimensional Conduction Extended Surfaces

enter image description here So I am having issue solving this problem, I solved one part by the fact that in the given distance of 2L , 2 tubes are involved so I can find the heat conducted per unit ...
2
votes
1answer
24 views

Heat Loss through a run of insulated piping

I've been racking my head around calculating the amount of heat loss still water will experience through a run of insulated piping. The water in the tank is maintained at roughly 550°F saturated, and ...
-1
votes
1answer
58 views

How can water mist lower a room's temperature?

Let me start off by saying that this is strictly NOT a homework question, so before you mark it as "homework", think. I was looking at how the water cools my body when it evaporates off it. Then I ...
1
vote
0answers
36 views

Calculation for lowering temperature in a room… room-fridge with water mist?

I was looking at how the water cools my body when it evaporates off it. Then I thought the specific heat capacity could be used to calculate how much energy (i.e heat) would be taken out of a room ...
2
votes
1answer
33 views

How to periodically shut down a recirculating hot water solar thermal system

I am posed with a scenario where a hot water solar thermal system has been setup. The system comprises of a cold water tank, heating arrays and then a hot water tank. The system is closed loop and ...
-1
votes
1answer
18 views

Comments on Patankar's book Numerical heat transfer and fluid flow

How to make comments on the book of Patankar, titled 'f' in 1980? Is it really worthy for beginners in the field of numerical heat transfer to read it? Besides, after finishing reading this book, what ...
1
vote
1answer
22 views

How to consider the dimension of a cylinder when computing its radiative budget?

I am trying to derive a heat budget model to estimate the temprature of very small a stationary vertical cylinder (1mm) under environmental conditions. Imagine a wooden stick. Simply put, I have R = ...
-1
votes
1answer
41 views

How do you calculate heat transfer due to solar radiation for a multi-layer wall given the incident solar radiation and wall specs?

Trying to come up with a MATLAB code for calculation of heat transfer due to incident radiation on a building's walls, would the solution involve using the conduction equation only? What would be the ...
0
votes
1answer
49 views

Stirling Engine Cooled Engine

Could a Stirling Engine replace the cooling system of an engine? Instead of having a clutch and fan attached to the main drive shaft to cool an engine, could a Stirling Engine and clutch share that ...
1
vote
2answers
43 views

Wall Humidity Condensation

Imagine you are in the mountains and it is very cold. The walls are colder than the air, so air close to the wall will lose heat to the wall, and by losing heat it might lose its humidity (water ...

1
2 3 4 5
7