Just a little fundamental question about capillary tubes:

Say, we have a capillary tube which is fed with liquid refrigerant only. It causes a mass flow of 10kg of refrigerant when the pressure drop over the tube is 10 bar.

Now, if we use the same capillary tube, and we maintain the pressure difference over the tube, but now it is fed with gaseous refrigerant. How would the mass flow be affected, and by what (approximate) factor?

The reason I ask this, is that if mass flow drops significantly when the captube is fed with a gas/liquid mixture, this fact can be used to build a system with a captube which will work with varying load. All that is needed for this is a well-insulated accumulator after the receiver which can hold the total refrigerant charge present in the system. As soon as load on the evaporator drops, liquid refrigerant accumulates in the accumulator, causing the capillary tube to starve, and thus reducing it's capacity to match the load. When load increases again, evaporator pressure rises, starvation of the captube decreases, and captube capacity increases. At least, that is what I think what happens.

It is just an idea. I have not yet found the ultimate metering solution for a small (25-100W) and highly varying (>400%) load like a microprocessor. Those chips spit out only a few Watts when running idle, but running calculation intensive tasks with highly optimized math cores such as simulation software and games can raise heat production to many times the idle heat production. TEV's have problems with the lowest load situation, captubes have problems with the varying load. So I keep searching for better methods to cope with this situation.