[AR] Re: Nozzle shapes
- From: Ben Brockert <wikkit@xxxxxxxxx>
- To: "contact@xxxxxxx" <contact@xxxxxxx>
- Date: Wed, 13 Nov 2013 01:37:54 -0700
Thanks, Alexander. Sounds like the Q&A was based on having only looked
closely at one of the older engines.
Swirl injectors are in a similar state in the US as pintles; there are
people who use them but they're not very common.
Ben
On Wed, Nov 13, 2013 at 1:25 AM, contact@xxxxxxx <contact@xxxxxxx> wrote:
> I have seen this Q&A before, and was always wondering what exactly is meant
> by "more conical Soviet nozzles" and "worse combustion efficiency in Soviet
> chambers"?
>
> Method to design optimal nozzle contour was developed in Soviet Union 1 or 2
> years earlier than Rao developed similar method in USA. First engine with
> such nozzle was RD-219 for R-16, developed in 1958-1961. Since then all
> Soviet engines were developed with optimal nozzle contour, including of
> course all staged-combustion engines.
>
> The only engines with "conical" nozzles (actually - with "radius" nozzles)
> were RD-107 and RD-210...214, developed in first half of 1950s.
>
> Concerning combustion efficiency: "traditionally" almost all Soviet engines
> had swirl injector elements (either single or two components) which provide
> better atomization and mixing compared to jet injector elements
> "traditionally" used in US engines. Since earlier 1960s, almost all engines
> developed in USSR were staged-combustion engines, with swirl injectors for
> liquid component and jet injectors for hot gaseous component. Such
> combination provides even better atomization and mixing.
>
>
> Best regards
>
> Alexander Ponomarenko
> http://www.propulsion-analysis.com
>
>
>
>> Ben Brockert <wikkit@xxxxxxxxx> hat am 12. November 2013 um 20:35
>> geschrieben:
>>
>>
>> Anyone have further info to back this up, or Russian nozzle design
>> logic translated into English?
>>
>> From a powerpoint on nozzles by D. R. Kirk of FIT:
>>
>> Q: Why do U.S. nozzles look more like a polynomial contour and Soviet
>> nozzles look more conical?
>>
>> A: (Jim Glass, Rocketdyne)
>>
>> Interestingly, Soviet nozzle designs have a 'different' look to them
>> than typical US designs. US designs are ‘truncated Rao optimum’
>> bells, usually designed by method-of-characteristics methods. Soviet
>> nozzles, to US eyes, look more conical than ours. Ours have that nice
>> ‘parabolic’ look to them - less conical. One would suppose the
>> Russians are fully capable of running M-O-C and CFD codes and thus
>> their nozzles, if optimum, should look ‘just like’ ours. Since they
>> don't, I've always wondered if they know something we do not. In my
>> experience, the US is better at combustion engineering (minimal C-star
>> losses) but has fairly substantial losses in the nozzle (aerodynamic
>> losses). The Russians tend to reverse this, throwing away huge gobs
>> of energy due to incomplete combustion and then using a very efficient
>> expansion process to get some of it back. The bottom line is both
>> design approaches appear to yield roughly the same Isp efficiency...
>> One wonders what would happen if one were to mate a US combustor to a
>> Russian nozzle…
>>
Other related posts:
