Hi everyone
We are looking for thermocouples with very small size. I can call them Micro-thermocouples. We need to measure the internal walls' temperatures inside a special heat exchanger design. So, we have small channels with the area as triangular, roughly 0.5x12x12mm. We want to place the thermocouples inside the channel and on the wall.
So, has anyone idea for which type of thermocouples could be used ?and is there such a micro-thermocouple to sense the temperature between 0-250c?
best regards
If your system is steady, measurement would not be difficult. You might be able to expose the thermocouple bare bead on the surface. You may weld AWG 40 K or J or T type wires to form the small bead. Just make sure the surface flat. Similar measurement in the injection molds can be found by article search. If you have to acquire a transient temperature history, the accuracy will be influenced by the wall material properties, thermocouple bead size and the fluid properties. The time constant will be greatly affected by the thermocouple itself and the installation environment.
Thanks Leander Boer
for your replyWe have found this type of PT sensors but it still big to my channel. So we asked a German company if it is possible to make it smaller. But, Leander Boer
, are you saying the thermocouple loses its accuracy once we make it smaller?
Thanks Sun Kyoung Kim for your reply
Do you mean welding two type wires in one junction on the wall surface?
Another thing, in this way, do I need to cover this junction on the surface with insulated material because I am looking only for the wall or surface temperature?
You don't have do that on the surface. I meant creation of the thermocouple bead by welding two thermocouple wires. Also, you don't have to cover the surface. Just take care of electric insulation and proper grounding to suppress possible noises. Covering the junction is not for accuracy but for reliability.
There are many issues in this measurement. If the bulk thermal diffusivity of the thermocouple is close to that of the wall, the interface temperature will be accurately attained as long as thermal no slip is guaranteed there. If the wall is polymer, you will basically measure the fluid temperature on the wall.
- Badges
- Science topic
- Similar topics
- Methodology
- Research Methodology
- Research Papers