Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Capillary tube

Status
Not open for further replies.

Lukezo

Mechanical
Jan 16, 2020
30
Hi,

can you please ellaborate on topic of ordinary capillary tube

In particular, I am interested in bubble entering the tube

Thanks in advance,
lukezo
 
Replies continue below

Recommended for you

Get a copy of a thermodynamics textbook and look up the subject of refrigeration and air conditioning which will detail the function of capillary tubes and the analysis performed on capillary tubes.
 
I suspect that your interest is in refrigeration and air conditioning equipment in which capillary tubes play an important function. Bubbles entering a capillary tube will be under high pressure and as the bubbles travel inside and exit the capillary tube, they will increase in size due to the pressure reduction and also the bubble temperature will get colder. When you study the relevant chapters in a thermodynamics text book you will come across terms such as enthalpy, entropy, quality, specific volume, saturated liquid and vapor lines, saturated and superheated region, and much more so be familiar with those terms. It is also important to study the Mollier diagram of the fluid in which the bubble appears and pay attention where on the Mollier diagram the attributes of the fluid travelling through the capillary tube are located.
 
Just think about the difference between trying to drink milk vs. whipped cream through a straw.
 
What requires bigger pressure difference in your opinion?

I prefer tea
 
The evaporator load and condenser load control the pressure drop.
The pressure drop determines the bubbliness.
The bubbliness determines the density.
The density determines the mass flow.
The mass flow determines the evaporator and condenser load.
Repeat.


 
I'm asking solely from capillary tube point of view as an element of cooling cycle
 
What requires bigger entry pressure? REfrigerant with bubble or with no bubble at all?
 
What requires bigger entry pressure? REfrigerant with bubble or with no bubble at all?

It depends on the exit pressure.

Capillary tubes are all about pressure difference.

The refrigerant cycle is..... a cycle.

You need to think about it as a cycle. If you think about individual points in isolation you will fail to understand how it works.
 
The question refers to the change of condenser load. So if evaporator pressure and inlet and outlet stay same, how does subcool / bubble presence before capillary tube influence pressure of condenser? Obviously the pressure will change...
 
It is impossible for some things to "stay same" while other things change within the refrigerant cycle.

Everything is connected. If one thing changes everything else must also change to maintain the overall system balance.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor