First wall thermohydraulic model #349

Closed jonmaddock closed 3 months ago

In GitLab by @mkovari on Nov 26, 2015, 08:43

The first wall calculation (subroutine iterate_fw in hcpb.f90) is very complicated, and causes frequent problems. I propose to replace it, as described below.

The thickness of the pipe wall sufficient to withstand the pressure is always very small - a fraction of a mm. In practice thermal stresses, corrosion and manufacturing issues will determine the thickness, so this is now an input. (This is additional to the armour thickness.)

The maximum temperature at the front face is calculated, and a constraint is available to limit this temperature. The first wall channel length affects this, as it determines the flow speed, so it is available as an iteration variable. Note it is no longer derived from the size and shape of the blanket module.

Strictly speaking since the first wall temperature is not known to start with, the thermal conductivity and heat transfer coefficient are not known. To get round this the global variable tpeak (peak first wall temperature) is now initialised to 873 K. Its value converges as VMCON converges.

The LeClaire formula for circular pipes is NOT used. It gives an unrealistically small temperature differential, as the wall thickness is the same all the way round, and the surface area is bigger than that of a flat wall. Instead two simple approximations are used:

See attached file.

It would be good to have an input for the reduction in thermal conductivity due to irradiation.

afwi /0.008/ : inner radius of inboard first wall/blanket coolant channels OBSO LETE (m)
afwo /0.008/ : inner radius of outboard first wall/blanket coolant channels OBS OLETE (m
fwcoolant /helium/ : first wall coolant (can be different from blanket coolant) 'helium' or 'water' (15/11/27)
fw_wall /0.003/ : wall thickness of first wall coolant channels (m) (15/11/27)
afw /0.006/ : radius of first wall cooling channels (m) (27/11/15)
pitch /0.020/ : pitch of first wall cooling channels (m) (27/11/15)
fwinlet /623/ : inlet temperature of first wall coolant (K) (15/11/27)
fwoutlet /823/ : outlet temperature of first wall coolant (K) (15/11/27)
fwpressure /15.5e6/ : first wall coolant pressure (Pa) (secondary_cycle>1)
tpeak : peak first wall temperature (K) (15/11/27)
roughness /1e-6/ : first wall channel roughness epsilon (m) (15/11/27)
fw_channel_length /4.0/ : Length of a single first wall channel (all in paralle l) (m) ( (iteration variable 114, useful for constraint equation 39)
peaking_factor /1.0/ : peaking factor for first wall heat loads (15/11/27) (Applied separately to inboard and outboard loads. Applies to both neutron and surface loads.)
blpressure /15.5e6/ : blanket coolant pressure (Pa) (secondary_cycle>1) (15/11/ 27)
inlet_temp /573.0/ : inlet temperature of blanket coolant (K) (secondary_cycle >1) (15/
outlet_temp /823.0/ : outlet temperature of blanket coolant (K) (15/11/27)
    (secondary_cycle>1);
    input if coolwh=1 (helium), calculated if coolwh=2 (water)

coolp /15.5e6/ : blanket coolant pressure (Pa) stellarator ONLY (15/11/27)

First_wall_geometry_for_PROCESS.docx

In GitLab by @mkovari on Dec 7, 2015, 11:41

mentioned in commit 2acc3d0c32247802c530442b3384a3df952d24a9

In GitLab by @mkovari on Dec 7, 2015, 11:41

mentioned in commit 8fbb0bdae53d4d5358d42d266a58b6b4201acf56

In GitLab by @mkovari on Dec 7, 2015, 11:41

mentioned in commit e728c91b78b4b7e91abcd0da9c6e6c5d75456a92

In GitLab by @mkovari on Dec 7, 2015, 11:49

Must check the Shimwell TBR model, as this sets fwith and fwoth directly.

In GitLab by @mkovari on Jan 7, 2016, 15:28

Benchmarked against THAMES, a more detailed therm-hydraulic model, with ANSYS thermal conduction.

PROCESS: First wall temperature (excluding armour) (K) (tpeakfw) 865
THAMES_: Max. Temperature in Structure (Tmax) [°C]: ____ 603.74 = 877 K
Temperature difference = 12 K

PROCESS: Pumping power, one channel, efficiency =0.9 (W): 3073
THAMES_: Pumping power, one channel, efficiency =0.9 (W): 3026
Difference 1.6%

z4_Thames_Results.txt

First_wall_thermohydraulics.xlsx

ANSYS temperature profiles from THAMES:
(\\msrv-fusiondc\KDrive\Power Plant Physics and Technology\PROCESS\blanket_model\Thames_Ansys000.png)

Thames_Ansys002

In GitLab by @hlux on Jun 22, 2016, 13:24

Title changed from First wall pipe wall thickness to First wall thermohydraulic model

In GitLab by @mkovari on May 23, 2023, 13:13

@timothy-nunn @jonmaddock I can't open any of the attachments in this issue. Error message:

Secure Connection Failed
An error occurred during a connection to git.ccfe.ac.uk:8080. PR_END_OF_FILE_ERROR
Error code: PR_END_OF_FILE_ERROR
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.

Can you help?

In GitLab by @timothy-nunn on May 25, 2023, 17:19

reopened

In GitLab by @timothy-nunn on May 25, 2023, 17:22

I'm afraid the same is happening to me too. I have reopened the issue to see if maybe that is what caused this. I will leave it a bit to see if they reappear but they are probably lost.

Thames_Ansys000

Thames_Ansys002

z4_Thames_Results.txt First wall thermohydraulics.xlsx

ukaea / PROCESS

First wall thermohydraulic model #349