Heat Pipe-Based DEMO Divertor Target Concept: High Heat Flux Performance Evaluation
<p>EU-DEMO divertor concept featuring a heat-pipe-based target from [<xref ref-type="bibr" rid="B1-jne-04-00021">1</xref>]: (<bold>a</bold>) target concept and its integration with the divertor cassette; (<bold>b</bold>) DIV-HP heat pipe unit dimensioned with proposed tungsten armor.</p> "> Figure 2
<p>Depiction of HPEE. (<bold>a</bold>) Depiction with dimensions of HPEE evaporator-end with W-plate; (<bold>b</bold>) top view of the evaporator surface with W-plate and protective cover.</p> "> Figure 3
<p>Porous structure on CuCrZr plate: (<bold>a</bold>) original shape; (<bold>b</bold>) version with channels.</p> "> Figure 4
<p>Inner view of HPEE mock-up: (<bold>a</bold>) illustration of the reservoir; (<bold>b</bold>) manufactured grooves and sintered porous evaporator.</p> "> Figure 5
<p>HPEE mock-up: (<bold>a</bold>) cross-section through the mock-up with dimensions; (<bold>b</bold>) photograph of the HPEE mock-up.</p> "> Figure 6
<p>Temperature measurement arrangement of the FHP mock-up: (<bold>a</bold>) condenser wall temperature measurements (T-HP05:HP07); (<bold>b</bold>) vapor temperature measurements (T-HP03:HP04); (<bold>c</bold>) loaded surface temperature measurements (T-HP08:HP11).</p> "> Figure 7
<p>Experimental setup in the laboratory.</p> "> Figure 8
<p>Laserline LDF 20000-200: (<bold>a</bold>) laser machine; (<bold>b</bold>) Zoom laser optic below the vacuum vessel; (<bold>c</bold>) laser spot size 19 × 19 mm<sup>2</sup>.</p> "> Figure 9
<p>Structure of electric copper heater: (<bold>a</bold>) assembly illustration; (<bold>b</bold>) installation with ceramic isolation.</p> "> Figure 10
<p>Coolant system used for mock-up: (<bold>a</bold>) illustration; (<bold>b</bold>) finalized nozzle heads.</p> "> Figure 11
<p>Transient measurement at the coolant inlet and outlet with laser power of 300 W: (<bold>a</bold>) temperature; (<bold>b</bold>) enthalpy.</p> "> Figure 12
<p>Comparison of the enthalpy and calorimetric evaluation of the power with 300 and 325 W: enthalpy-the red curves indicate the enthalpy calculated at the time earlier than time t with time lag dt; power-the orange curves indicate the power calculated with Equation (2); for comparison, the blue curves show the power calculated without accounting for the time delay.</p> "> Figure 13
<p>Status of the laser-heated surface after the first series of tests: (<bold>a</bold>) mock-up surface—the dark-gray area indicates that the load was applied eccentrically, only partially heating the tungsten armor as intended, wherein a significant part of the load is applied to the steel ring holding the armor; (<bold>b</bold>) shielding plate’s surface is heated on the other part.</p> "> Figure 14
<p>Mock-up-1 temperature evolution with liquid inventory for 1 MW/m<sup>2</sup> and laser calorimetric power: (<bold>a</bold>) 150 W (heat flux: 0.3 MW/m<sup>2</sup>); (<bold>b</bold>) 400 W (heat flux: 0.82 MW/m<sup>2</sup>); (<bold>c</bold>) 500 W (heat flux: 1.0 MW/m<sup>2</sup>).</p> "> Figure 15
<p>Vapor temperature of mock-up-1(heated by laser power) as a function of the heat flux.</p> "> Figure 16
<p>Heat flux versus average wall superheated ΔT of mock-up 1 with laser.</p> "> Figure 17
<p>Mock-up-1 temperature evolution with liquid inventory for 1 MW/m<sup>2</sup> and electric copper heater calorimetric power: (<bold>a</bold>) 300, 320, and 360 W (heat flux: 0.61, 0.65, and 0.73 MW/m<sup>2</sup>); (<bold>b</bold>) 400, 440, and 470 W (heat flux: 0.82, 0.9, and 0.9 MW/m<sup>2</sup>).</p> "> Figure 18
<p>Variation in the temperature drop between the evaporator and condenser with the transferred power for all testing campaigns.</p> "> Figure 19
<p>Mock-up-2’s temperature evolution with liquid inventory for 1 MW/m<sup>2</sup> and electric copper heater calorimetric power: (<bold>a</bold>) 100, 200, and 300 W (heat flux: 0.2, 0.4, and 0.6 MW/m<sup>2</sup>); (<bold>b</bold>) 320, 400, 500, and 600 W (heat flux: 0.65, 0.8, 1.0, and 1.2 MW/m<sup>2</sup>.</p> "> Figure 20
<p>Vapor temperature of mock-up-2 with electric heater as a function of the heat flux.</p> "> Figure 21
<p>Heat flux versus average wall superheated ΔT of mock-up 1 heated via electric heater.</p> ">
Abstract
:1. Introduction
2. Mock-Up Design and Layout of the Experimental Setup
2.1. Evaporator
2.2. Wick Structure
- The thickness of the wick porous B200 on the CuCrZr plate was increased from 1 mm to 2 mm due to the larger grain size of the sintered material (B200);
- The maximum heat flux that the B200-mockup could receive was only 4 MW/m2, which was mainly due to the sintered material’s low heat conductivity (40 W/m/K), thus resulting in an increased wall temperature. The heat flux of 4 MW/m2 corresponds to the loading at which the CuCrZr wall approaches its operational limits.
2.3. Reservoir for Volume Change
2.4. Condenser
2.5. Instrumentation of the HPEE Mock-Up
2.6. Experimental Setup
2.6.1. Heat Source Systems
2.6.2. External Cooling System/Heat Sink System for HPEE
2.6.3. Calorimetric Evaluation of the Power Applied to the Mock-Up
3. Results
3.1. Consideration of the Evaluation of the Transported Power via the Calorimetric Method
3.2. Temperature Measurements of Mock-Up-1 through the Laser Machine Test
3.3. Temperature Measurements of Mock-Up-1 via the Electric Copper Heater Test
3.4. Temperature Measurements of Mock-Up-2 via the Electric Copper Heater Test
4. Conclusions
- The laser heat source can heat the evaporator immediately without requiring other heat transport material and can operate at a high heat flux level. However, the problem of alignment renders the heated surface difficult to control; further, this method is limited by the maximum laser window working temperature of 150 °C at 1 kW laser power. Above this temperature, the vacuum tightness is compromised due to the loss of the gasket’s elasticity and the signs of the deterioration of the window material, for which the latter had to be replaced.
- The electric copper heater can effectively heat the evaporator at the correct position. However, a very long time is required to reach a steady state for full power, and a stepwise application of the heating power to the mock-up is impossible. An electric copper heater’s maximum heat flux is around 2 MW/m2 due to its working temperature of 750 °C.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Parameters | Symbol | Value |
---|---|---|
Width of groove | w | 0.3 mm |
Depth of groove in the evaporator | h | 0.65 mm |
Number of grooves | Ng | 125 |
Sintered porous configuration for mock-up-1 | ||
Height of porous evaporator (Bronze) | he | 2 mm |
The grain size of the sinter’s | rp | ~400 um |
porosity | ε | 0.47 |
Sintered porous configuration for mock-up-2 | ||
Height of porous evaporator (Bronze) | he | 2 mm |
The grain size of the sinter’s | rp | ~400 um |
porosity | ε | 0.47 |
Width of porous channels | wpc | 1 mm |
Depth of porous channels | hpc | 1 mm |
Number of porous channels and their length | Npc | 4 × 10 mm + 4 × 6 mm |
Heat Load Range | Liquid Inventory |
---|---|
0–1 MW/m2 | 1.5 mL |
1–5 MW/m2 | 2 mL |
5–20 MW/m2 | 2.5 mL |
Parameters | Symbol | Value |
---|---|---|
The outer diameter of the evaporator | de,o | 33.4 mm |
The inner diameter of the evaporator | de,i | 25 mm |
The thickness of the evaporator wall (CuCrZr) | tt | 2 mm |
Outer diameter of condenser | dcond | 60.3 mm |
Inner diameter of condenser | db | 52 mm |
The thickness of the condenser wall (CuCrZr) | tc | 10 mm |
The inner height of the adiabatic zone | had | 75 mm |
Incision angle | β | 19.5° |
Evaporator protect plate (W) | tw | 2 mm |
Parameters | Symbol | Value |
---|---|---|
The inlet temperature of the coolant | θin | 20 °C |
Pressure | p | 4 Bar |
The inner diameter of the coolant pipe | dcoolant | 60.3 mm |
The thickness of the coolant box wall (steel) | tcool | 4 mm |
Number of jets | Nn | 7 |
The inner diameter of the jet | D | 3 mm |
Distance between jet and bottom of FHP | H | 15 mm |
Component | Location | Model | Accuracy |
---|---|---|---|
Temperature T-01 | Coolant inlet | RTD | ±(0.15 + 0.002 ×|T|) (Class A) [DIN43760] |
Temperature T-02 | Coolant outlet | RTD | |
Pressure P-01 | Coolant inlet | PM-5060-C | ≤±0.5% of span [IEC 61298-2] |
Pressure P-02 | Coolant outlet | PM-5060-C | |
The volume flow rate sensor F-01 | Coolant outlet | H250 M40 | 1.6% of measured value VDI/VDE 3513-2 |
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Wen, W.; Ghidersa, B.-E.; Hering, W.; Starflinger, J.; Stieglitz, R. Heat Pipe-Based DEMO Divertor Target Concept: High Heat Flux Performance Evaluation. J. Nucl. Eng. 2023, 4, 278-296. https://doi.org/10.3390/jne4010021
Wen W, Ghidersa B-E, Hering W, Starflinger J, Stieglitz R. Heat Pipe-Based DEMO Divertor Target Concept: High Heat Flux Performance Evaluation. Journal of Nuclear Engineering. 2023; 4(1):278-296. https://doi.org/10.3390/jne4010021
Chicago/Turabian StyleWen, Wen, Bradut-Eugen Ghidersa, Wolfgang Hering, Jörg Starflinger, and Robert Stieglitz. 2023. "Heat Pipe-Based DEMO Divertor Target Concept: High Heat Flux Performance Evaluation" Journal of Nuclear Engineering 4, no. 1: 278-296. https://doi.org/10.3390/jne4010021