Fórum Defesa Brasil

alexandre lemos escreveu:Ficaria a cargo de uma companhia:Abengoa?

Fuel cell ? Etanol ? No compreendo ...

Koslova escreveu: apenas 7227W ou seja cerca de 500 vezes menos energia do que navegar a 24 nós.

Koslova escreveu:Ciclo Water

A mais antiga é o sistema Water, que utiliza H2O2 concentrado

Carlos Mathias escreveu:É Koslova, como o pessoal disse aí, depois desta pequena aula não tem muito o que debater. Eu pelo menos não manjo nada de AIPs. Conhecia os LPs...Alguém lembra deles?

Koslova escreveu:Deixa ver se entendi: um submarino de quase 2000 toneladas pode navegar a 3 nós com pouco mais energia que um chuveiro elétrico???

Seria algo como 10Hp. Existem algumas questões que não são consideradas na teoria que são importantes na pratica, a principal delas é o atrito do eixo que consumiria uma boa parcela de energia, mas a potencia de propusão estaria na pratica a algumas poucas dezenas de HP´s.


Água oxigenada, aquela que as mulheres usam para descolorir o cabelo? Isso serve para algo mais???


O peroxido de hidrogênio teria que estar muito mais concentrado do que o que compramos na farmacia. Quando na presença de um catalisador, como a Prata o H2O2 se decompõe sem H2O + Oxigenio, estes gases de saida são utilizados para mover uma turbina gerando potencia mecânica.

A equipe de Von Brauhn utilizava o H2O2 para gerar potencia mecânica que movimentava duas bombas, uma de alcool e outra de Oxigenio liquido que alimentava a camara de combustão.

Os foguetes dos anos 50 utilizavam esta técnica que chamamos de "mono-propelente" para mover as suas turbo bombas, hoje o unico foguete a utilizar o H2O2 é o Soyuz, aquele que ontem lançou a Soyuz TMA-9 rumo a ISS.

Os impulsores RD-107 desta familia de foguetes foram projetados em 1955, bem no auge desta técnica, depois outras técnicas mais modernas de bombeamento surgiram e aposentaram um pouco o emprego do H2O2 em propulsão espacial e AIP

Koslova escreveu:

alexandre lemos escreveu:Ficaria a cargo de uma companhia:Abengoa?

Fuel cell ? Etanol ? No compreendo ...

Existem algumas classe de celulas de combustiveis chamadas DEFC Direct-ethanol fuel cell, que utiliza o hidrogênio presente no alcool para a geração de eletricidade.

Koslova escreveu:

Delta Dagger escreveu:
Obrigado pelas valiosas informações, gostaria muito de saber o motivo da não escolha do AIP pela MB, já que este me parece algo muito útil.

Eu normalmente escrevo estas mensagens maiores durante viagens longas como forma de passar o tempo, o problema é que ultimamente nem tem dado tempo para escrever sobre este tipo de assunto.....

Achei que este tópico teria mais "Ibope" foram apenas 7 respostas, qualquer bobeira de "Corinthians x Flamengo" tem uma 10 vezes mais mensagens que isto...rs


Abraços

Koslova escreveu:(...) vou ver se consigo um tempinho mais tarde para escrever sobre a importancia tática do AIP, os motivos que levaram Brasil e Chile a abrirem mãos do AIP e até que ponto isto teria sido uma descisão técnica ou teria sido uma influencia cultural destas marinhas durante o processo de escolha.



Abraços

THE AIP SYSTEM
During World War II the Kriegsmarine had experimented
with a closed-cycle diesel system as an alternative
to the Walter perhydrol-fuelled turbine.
Postwar, the Americans and British experimented
with high-test peroxide, but the Soviet Navy was
more impressed with the Kreislauf system, and
designed the Project 615 'Quebec' class coastal
submarines around the concept. What the Soviets
called a 'single propulsion system' ran submerged on
an internal supply of liquid oxygen (LOX). The
oxygen was added after the exhaust gases were
filtered through a lime-based chemical absorbent. The
boat could also run its Kreislauf diesel in the normal
way, using a schnorkel.
The 'Quebec' had three engines, a 32D 900bhp
diesel on the centre shaft and two M-50P 700bhp
diesels on the outer shafts. In addition a lOOhp 'creep'
motor was coupled to the centre shaft and a back-up
diesel-generator aft. The boat could be run at slow
speed using the centreline diesel only. Soviet records
suggest that experiments had started before 1941,
probably with the small coastal boat M.92, and other
closed-cycle designs were prepared after the
'Quebec'. Because LOX cannot be stored for any
great length of time these 467-tonne (460-ton) boats
could not operate far from a base. It was also a
dangerous system; at least seven suffered explosions,
and one of these, M.256, sank after being flooded
during firefighting efforts. One boat with the Walter
turbine AIP system was built, the 965-tonne (950-ton)
Project 617 S.99, known to NATO as the 'Whale'
type. The 5.99 made 315 dives using her Walter
system, in 1956-9, but in May 1959 she was badly
damaged by an explosion, and was never repaired.
After these boats were decommissioned in the early
1960s interest in AIP lapsed, but recently the Russian
Rubin Bureau announced that it can offer an AIP
system for the new 'Amur' type SSK. Information
released shows that it is a fuel-cell system (see
below).
The most successful AIP system so far is the
Stirling engine. Developed from a patent dating back
to 1816, the Stirling cycle burns diesel fuel in pure
oxygen, in a pressure vessel. The Swedish submarine
builders Kockums AB of Malmö own the rights to the
Stirling engine, and tested its V4-275R 75kW engine
in the serving submarine Nacken. This proved
successful, with less vibration than a conventional
diesel-generator, and considerably lower noise levels.
In fact it is possible to conduct a conversation while
standing alongside a running Stirling engine. Since
then the A 19 type 'Gotland' class have been built
from the outset with Stirling engines, and the system
has been evaluated by a number of navies. Despite
rumours of submarines running entirely on four
Stirling engines, Kockums denies this, pointing out
that the amount of LOX required would be impossible
to fit into the submarine's hull.
The German Navy followed a different route,
funding Siemens and HDW in the development of a
Proton Exchange Membrane (PEM) fuel cell capable
of generating 40kW. As with the Stirling principle, the
idea is an old one, dating back to 1839. In essence a
fuel-cell reverses the process of electrolysis, using a
chemical reaction to combine hydrogen and oxygen,
thereby producing electrical energy, heat and water.
The heart of the PEM system is a solid polymer
electrolyte in the form of an ion exchange membrane
in contract with a platinum catalyst and carbon paper
electrodes. The membrane is positioned between the
fluid flow field and the cooling units in such a manner
that hydrogen ions pass through it and combine with
hydrogen anions. As long as hydrogen and oxygen are
supplied the fuel cell will continue to produce power.
A single fuel cell cannot produce more than 1.48V
and therefore several must be stacked to form a
module. The main drawback to the system is the cost
of materials, and HD W has so far not offered it for
export. The Federal German Navy tested a lOOkW
prototype installation in the old Type 205 boat U.I,
and the Type 212 boats currently under construction
will have a 400kW version.
OTHER AIP SYSTEMS
After the fuel cell trials the U.I was made available by
the Navy to TNSW for trials of a closed-cycle diesel
AIP system (CCD). This has the advantage of being
simple, the most complex part being the waterabsorption
system developed by Cosworth
Engineering. The engine exhaust gas is 'scrubbed'
with water to remove the carbon dioxide, and in the
same process the water vapour is condensed. Surplus
carbon dioxide is eliminated by adding a small
quantity of argon gas. The great virtue of the CCD
Left: HMS Ursula, the third of the 'Upholder' class. In
Canadian service she will be armed with the US Navy's
Mk 48 Model 4 torpedo and a Canadian towed sonar array.
system is its use of the same diesel for schnorkelling
or as an AIP unit, a great saving in cost. The system is
being marketed by TNSW and RDM (as the Spectre
system). The TNSW trials with U.I had the rare
benefit of comparing like with like: both the fuel cell
and the CCD being tested in the same hull.
The only other AIP system available is the French
(Module d'Energie Sous-Marin Autonome [MESMA])
system, which uses an oxygen-ethanol fuelled steam
turbine. Conceived in the early 1980s by the Bertin
company, it was taken up by DCN, the French Navy's
design and procurement bureau, in collaboration with
Empresa National Bazan in Spain. Although the
French Navy has not installed MESMA in a submarine,
it has been sold to Pakistan for fitting to new
Agosta-90B type SSKs.
The excitement over AIP has led to exaggerated
claims about its potential. Some commentators claim
that the advent of AIP has created a third category of
submarine, the SSK+AIP, but the fact remains that
only one navy has a modern AIP system operating.
Three more will have systems in service after the turn
of the century (counting Italy's acquisition of the Type
212 design), but a number of experienced operators
are still not sufficiently convinced to commit
themselves.
FUTURE DEVELOPMENTS
AIP enthusiasts point to potential developments. The
CCD system has great promise, with such improvements
as electronic fuel-injection and electronically
actuated valves. These improvements will allow the
operator to select engine-characteristics from a menu
of choices. The Solid Oxide Fuel Cell (SOFC) would
use natural gas as fuel, resulting in a single propulsion
system for surface and submerged propulsion.
Siemens is also known to be working on a fuel cell
using methanol as the base fuel to generate hydrogen.

alexandre lemos escreveu:
1) Sem pretender abusar, qual a eficiência desta célula com degradação do etanol comparada com os demais ? Haveria facilidades quanto ao reabastecimento nos portos ?

tulio escreveu:

Koslova escreveu:(...) vou ver se consigo um tempinho mais tarde para escrever sobre a importancia tática do AIP, os motivos que levaram Brasil e Chile a abrirem mãos do AIP e até que ponto isto teria sido uma descisão técnica ou teria sido uma influencia cultural destas marinhas durante o processo de escolha.



Abraços

Por caridade, minha amiga, que seja apenas MAIS TARDE e não DEUS SABE QUANDO, tem um balaio de gente aqui se roendo de curiosidade, POWS!!!

Tudo de bão...

tulio escreveu:

Koslova escreveu:(...) vou ver se consigo um tempinho mais tarde para escrever sobre a importancia tática do AIP, os motivos que levaram Brasil e Chile a abrirem mãos do AIP e até que ponto isto teria sido uma descisão técnica ou teria sido uma influencia cultural destas marinhas durante o processo de escolha.



Abraços

Por caridade, minha amiga, que seja apenas MAIS TARDE e não DEUS SABE QUANDO, tem um balaio de gente aqui se roendo de curiosidade, POWS!!!

Tudo de bão...