# Doubt regarding Solidworks Flow Simulation of  Heat Exchanger!

Question asked by Gerardo Perdomo on Nov 25, 2015
Latest reply on Nov 26, 2015 by Andreas Klumpp

Hi there, I am currently starting to use Solidworks Flow Simulation 2014 for some assignment on Heat exchangers and I have some questions about how it works. First I started with the Wizard, I specified the units, chose internal study with conduction in solids, chose the fluids (lets supose blood and water) and solid material, and decided to go with adiabatic wall. I left the level of the initial mesh in 3 and then started specifying the fluid domains and the boundary conditions.

For my example I will be simulating the heating of blood using hot water circulating around the tube in which the blood flows. So here are my conditions:

1. Volume Flow for the blood Inlet with 30 Celsius

2. Environmental Pressure for the blood outlet

3. Volume Flow of Hot water Inlet at 50 Celsius

4. Static Pressure at the outlet

So my doubts begins when choosing the goals. What I want to know is to estimate either the water volume flow at a same temperature, or estimate the temperature at a same vol flow in order to get a final blood temperature of 40C at the outlet.

I have the option to choose diferent goals depending on what I want, but for the main purpose of this study I think on choosing a global goal of the temperature fluid,  global goal on temperature of solid and a surface goal at the lid on the blood outlet. I suppose that with those 3 goals it will be enough for this simulation, maybe an equation goal dividing the surface goal between 40. Any recommendations??

But well, things are getting a little complicate for me when I have the option of choosing between min avg max or bulk avg values. I ran some simulations to see the differences between avg and max, for example, and they are way different. I have readed on other forums discusions about those values but I havent really understand, if maybe someone can explain the differences of min avg max and bulk using some examples it would be awesome for me. Especially because English is not my native language so I struggle sometimes.

After specifying the goals and running the simulation I know there is a way to ''optimize'' or estimate values for a desire result with a Parametric Study. Since I only want to know the final temp of the blood I was thinking on using the Goal Optimization study and choosing as a parameter the temp of water or the volume flow of water with a range, and then for the outpout parameter I was planning on introducing equation goal to a target value of 1 (temp desired of blood/40=1)

Maybe there is a simpler way for the optimization without using the Eq Goal.

Thanks for any help,

Gerardo