Introduction
In this tutorial, we will build a simple model of system with a primary loop and secondary side. In the primary loop, we will be circulating helium using a pump. We will be adding heat in the core section and removing it in the heat exchanger section. The secondary side will be running liquid water.

Figure 1: Diagram of the system
We will gradually build the model step by step introducing the following basic concepts:
Fluid property system
Components
Postprocessors
Control logic
Functions
Closure system
Each step will be a complete working model that will be simulating a subset of the final model.
Problem Description
Figure 1 shows the diagram of the modeled system. The tables below list its physical parameters.
Table 1: Primary loop parameters
Parameter | Value (and unit) |
---|---|
Pressure | 1 MPa |
Temperature | 300 K |
Mass flow rate | 0.01 kg/s |
Fluid | helium |
Table 2: Core parameters
Parameter | Value and unit |
---|---|
Shape | Heating rod inside a square flow channel |
Core length | 1 m |
Side width | 8.7 cm |
Rod diameter | 2. cm |
Table 3: Heat exchanger parameters
Parameter | Value and unit |
---|---|
Inner diameter | 12 cm |
Wall thickness | 5 mm |
Outer diameter | 50 cm |
Length | 1.5 m |
Table 4: Secondary loop parameters
Parameter | Value and unit |
---|---|
Mass flow rate | 1 kg/s |
Fluid | Liquid water |