[AR] Re: OT Nozzle shapes
- From: Keith Henson <hkeithhenson@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Wed, 13 Nov 2013 11:12:01 -0800
On Wed, Nov 13, 2013 at 6:43 AM, Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx> wrote:
> Keith Henson wrote:
>>
>> On Wed, Nov 13, 2013 at 12:49 AM, Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx>
>> wrote:
>>
>>> Keith Henson wrote:
>>>
>>>> I have a fairly bizarre problem. Need to get rid of 3 GW of waste
>>>> heat from lasers in orbit. The pump diodes use a total flow of 60
>>>> cubic meters per second at 22 deg C inlet and 34 deg C outlet.
>>>
>>> Take the working temperature further down ? ( increases efficiency )
>>
>> The laser efficiency goes up as you take the working temperature down,
>> but not much.
>
> 300K to 100K can give you 50%
Do you have a reference for this?
> Other effects work against it, though looking around
> theres quite a bit of work around on cryogenically cooled laser diodes.
> so it must make some sense. ( But I haven't kept current in that area )
>>
>>> look into other coolants that are lighter and have less viscosity?
>>
>> It's hard to beat water
>>
>>> wild shot:
>>> find a way to compress (centrifuge ? ) the evaporated coolant
>>> to higher temperatures, radiate away the heat ...
>>
>> this is a possibility. It gets tricky not just because of the extra
>> energy needed to pump the heat uphill, but because the radiator walls
>> must be thicker to take the higher pressure.
>>
> What about that heat exchanger from the Sabre project :-?
I am reluctant to use heat exchangers at all because of the
temperature drop across the exchanger, even counter current ones.
Keith
> uwe
>
>
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