Catalin Daniel Iosif Technical University of Cluj-Napoca Student

Hello!

I need to asses the power (W/m2) entering an concrete structure from the ground surrounding it. But I don't know exactly which of the rate resulted I need to check. Using masking domain (Subdomain Boundary Rate Budget) is it the correct way of assessing it (see the picture)?

I am studying moulded walls equipped with pipes through which a fluid circulates in order to transform the moulded walls into heat exchangers that supply a heat pump. The pipes are caught to the reinforcement cage. However, in the numerical model, I replace the physical pipes with nodes acting like a source or sink of heat. The power set at the nodes represents the power demand during a season (by example 5 W/node in the hottest day of summer). I need to find out how much of the energy can be exchanged with the ground and how much of it is lost within the concrete and the excavation.

I understand, I hope, how the software calculates the conductivity after modeling two simple models. My conclusions are: Solid thermal conductivity = Bulk thermal conductivity when water is not present in the layer and Solid thermal conductivity together with fluid thermal conductivity = Bulk thermal conductivity when layer is saturated. The formula used is the empirical one: n*lambdafluid + (1-n)*lambdasolid = lambda bulk. Am I right? Thank you!

Thank you!

I don't find anything clear about this parameter. Also, I don't clearly understand how heat conductivity along with volumetric heat capacity is calculated based on porosity and fluid/solid properties. I will do some simple models to better understand the last two terms. Please, help me if you have an answer at hand. Thank you in advance!

Hello! How do you usually consider longitudinal/tranverse dispersivity values for heat transfer? Default, 0 or different?

When I use a simple model to see the influence of this parameter I observe huge differences in temperature field. The material I used is concrete, therefore I firstly set dispersivity to 0 in the first case (full homogenius) followed by setting default values (5m/0.5m) in the second case. The results are in the attached image.

There is any table showing the most correct values to consider based on different criteria?

Thank you!

Hello, again!

I need to find out the divergence [W/m3] of the flux by conduction and advection from FEFLOW. There is any way for finding them? Actually I don't really understand where should I look to find heat flow [W/m2] by conduction and advection followed by finding out their divergence. Maybe you can help me with this one.

Thank you!

I managed to succeed by using Triangle along with points. There is need for setting small point target size with a small graduation not distort the straight lines representing the walls contour. The nodes can be furthermore connected with lines, for an easily find the center point.

The main idea is that I need a certain distance between the node in all three directions. For example If I model a diaphragm wall having 6m length, 1.2m wide and 15m depth, I need to have nodes at 10cm from the edges, at 1m distance on one face and also at every meter in depth.

For example, in the image below, W - 1.2m, L - 6m, sp - 1m, c - 0.1m, D - 15m. I solve depth by defining slices, but what about the others?

Thank you!

This is the image.

Sorry If I don't get it, but do you mean like in the image below?

I made the lines using short lines of 1 meter. On the left side is before while on the right side is after I connect the dots. Even like this, it doesn't work.

Only when I draw connection lines without using the dots, by mouse clicking, then it works. I will ad the image on next one. Another way is to find a good refinement of the lines to obtain nodes at each 0.25 or 0.5 m, but it's not perfect.

Hello. In my model I need to set nodes at a certain distance. May I do this using meshing? I didn't find any solution for this using meshing therefore I tried to draw lines which intersections would represent the nodes I need. The problem is that when I am using "F2" key to define lines coordinates, FEFLOW crashes at meshing, using Grid Builder method. When I add lines using mouse click, it works. I saw that this topic was posted 5 years ago, but no solution was found. There is any way I can obtain a certain distance between nodes, rather than using lines?

Also, Triangle and Advance Front are not helping me if Grid Builder doesn't work, or maybe I don't know how to use them.

Thank you!