Digital twin of the MEPhI Thermohydraulic Floow Loop (THFL)
Virtual analog prototype
The test facility has two coolant movement circuits: a primary circulation loop for research into hydro-dynamics and heat transfer to liquid, and an auxiliary (secondary) circuit intended for removal of heat from the primary circulation loop. The total quantity of distilled water in the two circuits, with regard for the expansion tank and the feedwater tank, is 800 liters, and the pressure at the circuit’s upper point is atmospheric.
The primary circulation loop is equipped with a transparent quartz working volume which accommo-dates changeable working sections. Each working section is a bundle of fuel elements with different di-ameters, lattice types and lattice pitches. The fuel element is heated due to Joule heating when alternating electric current is passed through these and makes it possible to change, independently, the heat flux den-sity in each of them from zero to 5·105 W/m2 until nucleate boiling occurs. The coolant movement in the primary circuit may take place both in natural circulation conditions and in the process of the coolant forced movement (Re ≤ 5104). To ensure the difference of the coolant densities in the riser and downcomer portions, required for the natural circulation to occur, heat is supplied to and removed from the primary circuit coolant.
The coolant parameters are measured using temperature-sensitive sensors, pressure gages and flow me-ters the arrangement of which is shown in Fig. 2. The flow rate is measured using detachable ultrasonic flow meters installed on the circuit’s lower horizontal length (G1) and vertical downcomers (G2 and G3). Pressure is monitored at the primary circuit’s lowest (P1) and highest (P4) points, and the pressure differ-ence in the working volume is measured using two high-precision elastic element pressure gages (P2 and P3). The fluid flow temperature is measured using resistive platinum temperature-sensitive elements built in all angle elements of the structure (T1, T3, T4, and T6) and the T-joints (T2 and T5) and installed in the feedwater tank (T7) and the expansion tank (T8). Temperatures of the detachable heaters, the thermal in-sulation in the heated portions, and the environment are measured additionally.
Detailed information about the THFL can be found here.
THFL in virtual reality
The virtual prototype of the thermohydraulic flow loop is generated in the Unreal Engine 4 environ-ment which allows visualizing both the test facility and the processes in it using virtual reality tools. The major method to visualize the current physical processes is gradient coloration of textures. Instanta-neous temperature values, fluid velocity, or pressure are associated to the color map. The state of the shutoff valves is displayed using the gate valve colors, and the numerical values of the key measured pa-rameters are displayed in the virtual monitor on the room wall. Fig. 6 shows an example of the visualized fluid temperature distribution in the primary circulation circuit in a virtual reality.
Such virtual analogs are actively used in large corporations for personnel training. The possibility of creating a virtual educational laboratory work to support the educational process is assumed.
Planned functionality
At the moment, work is underway on the following functionality:
- Data exchange between the experimental facility and the digital twin in real time;
- The ability to control the digital twin from virtual reality;
- Creation of a digital twin in augmented reality.
