Hydraulic Problem: Fluid backing up into a closed tube

[halld]

Hello,

I am investigating a phenomenon known as "Blood reflux" and I am interested in the Hydraulic Principles I need to understand to solve a problem related to this. Here is the problem:

PROBLEM:
- A 20 gauge plastic tube is inserted into a vein with a 6mm diameter. The end of this plastic tube is oriented in the direction of flow. This 20 gauge plastic tube is flushed clear of blood and clamped 10cm from the tip residing in the 6mm vein. This effectively creates a tube closed on one end inserted into a flowing liquid. The clamped tube (assuming clamping is effective) will fill with blood some time later - this is known as reflux.

QUESTION:
- What principles of hydraulic theory effect this situation? I would like to learn about these principles and work to understand the mechanisms that are involved. Hopefully this will lead me to understand the circumstances that can cause this and then work to predict and prevent them.

Thanks.

 

[eljose79]

Thank you for your interest in hydraulic principles and their role in understanding and solving the problem of "Blood reflux". This is a complex and interesting phenomenon that requires a thorough understanding of hydraulic theory and its application in the human body.

Firstly, let's define hydraulic theory. This is the study of fluid mechanics, which includes the behavior of liquids and gases when subjected to pressure or flow. In the case of "Blood reflux", we are dealing with the flow of blood in a closed system, which is affected by both the properties of the liquid (blood) and the structure of the system (plastic tube and vein).

To understand the principles at play in this situation, we need to consider the concepts of pressure, flow, and resistance. In a closed system, such as the plastic tube inserted into the vein, pressure is created by the force of the liquid pushing against the walls of the tube. This pressure is directly related to the flow rate of the liquid, which is the volume of blood passing through a specific point in a given amount of time. The resistance in the system, which is the opposition to flow, is determined by the diameter and length of the tube, as well as the properties of the liquid.

In the case of "Blood reflux", the clamped tube presents a blockage in the flow of blood, which increases the pressure in the system. This increased pressure can cause the blood to flow back towards the closed end of the tube, leading to reflux. Additionally, the diameter of the tube and the properties of the blood, such as viscosity and density, also play a role in the occurrence of reflux.

To understand and predict this phenomenon, it is important to consider all these factors and their interactions in the context of hydraulic theory. By studying the principles of fluid mechanics and their application in the human body, we can gain a better understanding of the circumstances that can lead to "Blood reflux" and work towards preventing it.

I hope this helps in your investigation and understanding of this interesting problem. Feel free to ask any further questions or discuss any other insights you may have.