Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [temperature]

98 questions
13
votes
11 answers

Affixing a thermocouple to a surface

I'm looking for advice on how to attach a thermocouple to a metal surface in a fashion that's relatively temperature resistant (more-so than) glue. I've got some very fine gauge wire on hand to make the thermocouples and specialized spot welder…
Dan
  • 1,976
  • 1
  • 11
  • 17
13
votes
3 answers

Why does moving air feel cold?

I'm taking a thermodynamics class and had the following question. I was going to ask my professor directly, but it seems like a stupid question with a simple answer, so I thought I'd try my luck here in fear of embarrassment. When air flows through…
user01101001
  • 131
  • 1
  • 3
11
votes
1 answer

How does a microbolometer (IR camera) work?

I am currently doing a project which has led me to my first encounter with IR cameras, and I am therefore quite curious as to how they operate. Specifically, I would like to know the following How is heat converted to an electrical signal (current…
Julian
  • 273
  • 1
  • 8
9
votes
1 answer

How do I compute the force required to pierce HDPE?

I have a $2\text{ mm}$ sheet of HDPE at $280-320^{\circ}\text{ F}$. I want to pierce the skin of this sheet with a $2\text{ mm}$-high pin with a surface area of $3.33\text{ mm}^2$. The pin is also made of HDPE and has cooled completely. With the…
William B.
  • 363
  • 1
  • 5
7
votes
2 answers

How do train tracks handle really cold weather?

First of all, I'm interested in train track only, not the rolling stock. How are tracks built to cope with really cold weather? An example might be some place in Canada or Siberia. Ice would accumulate all the time, changing the shape of the…
DrZ214
  • 495
  • 1
  • 4
  • 15
7
votes
2 answers

How can I calculate the temperature rise of a circuit board for a given power dissipation and area?

I have a PCB of approximately 4" x 4". It has a single long spiraling trace on it. The trace is 50 mil 4 oz copper, so nominally it's good for something like twenty amps before it overheats. But this board overheats much faster. My supposition is…
Stephen Collings
  • 1,695
  • 17
  • 27
6
votes
2 answers

Having three heaters on single PCB

I posted this question on electronics SE, but was suggested that I post it here. I basically having three heaters (serpentine pattern) on a PCB (fiberglass board), as the following image shows: The ones at the end would be heated to 95°C, the ones…
Koushik S
  • 73
  • 3
6
votes
3 answers

O-Ring vs flat washer for air seal

I'm interested in whether a flat rubber washer or equivalent is good enough to replace an o-ring in a low pressure application (edit: I meant low pressure differential. My bad.). The reason is that flat washers might be easier to design for if you…
carveone
  • 337
  • 4
  • 9
5
votes
1 answer

Baffle vs Bottom Temperature Measurement/Control

In an industrial jacketed reactor, we have two temperature probes: one on a baffle the extends down about to the 50% fill line one built into reactor, very close to the bottom valve. When is it more reliable and practical to use one location…
tralston
  • 233
  • 2
  • 6
5
votes
2 answers

How do I determine the thermal resistance of a metal box?

Suppose I have a sealed enclosure, say this one from Hoffman: The box is 16"x12"x6", made of galvanized steel with a wall thickness of .0635" or .0785" (gauge 16 or 14). I'm planning to put some electronics in this box, which will generate an…
Stephen Collings
  • 1,695
  • 17
  • 27
5
votes
1 answer

Easily compute a good approximation of heat conductivity of cooled semi-vacuum (water vapor + air)

I am preparing a classroom demonstration about heat, including a demo of how a satellite loses heat only radiatively, since it's flying through a vacuum. I'd like to make the vacuum-production apparatus very simple and cheap. The kind of pump used…
Michael Turner
  • 53
  • 3
4
votes
3 answers

Controlling the temperature with high precision

I need to control the temperature with high precision, and for this task would be good a temperature controller with pt-100 sensor, something like this one PID Temperature Controller ITC-100. As I see that, it can be very simple: there is an input…
Antonio
  • 143
  • 3
4
votes
2 answers

Analog PID controller - settings wrt $V_{err}$ - setpoint always higher than room temp

I designed from scratch an analog PID controller to mantain a temperature selected in the range of 60 to 80ºC with a room temp say = 20ºC. The "plant" is a simple 4R7 5 W resistor heated by a PWM-controlled current (100% to 0% range). For any given…
atferrari
  • 41
  • 2
4
votes
1 answer

How to extract a building's heat isolation and thermal inertia based on temperature curves?

So imagine we have a house with some isolation and some thermal inertia. This house also has a heating system that turns on (starts heating) when the observed temperature curve goes below some predefined temperature threshold. I figured that in the…
Samy Geronymos
  • 141
  • 2
4
votes
3 answers

At which temperature and humidity should outside air be drawn inside?

I have a greenhouse that get’s mold in the winter because it’s to humid. I have now installed a heater and a ventilation system drawing outside air into the greenhouse. I wish to start the vent based on weather conditions however I cannot figure out…
Tiptop
  • 143
  • 3
1
2 3 4 5 6 7