항공무장 Rotating Detonation Engine - 기존 램제트의 대안

[백선호]

미국 DARPA가 공대공 미사일의 사거리를 늘리기 위해서 Rotating Detonation Engine이라는 새로운 엔진을 연구하고 있습니다. 

램제트나 RDE나 모두 연료와 공기를 같이 태우는데 램제트는 같은 압력에서 연료와 공기를 태우지만 RDE는 '같은 볼륨'으로 태운다고 하네요.

RDE는 기존 램제트보다 더 작게 만들 수 있어서 더 많은 연료를 실을 수 있다고 합니다.

In a ramjet or turbine, the fuel-air mixture is combusted at a constant pressure in a process known as deflagration.

In an RDE, the mixture is burned in an annular combustion chamber in a rotating wave of high-speed detonation at a constant volume. 

“These constant-volume detonations make ram-RDE combustors more compact and operable at speeds beginning much lower than conventional ramjets,” DARPA says.

The more compact size of a ram-RDE combustor allows the missile to carry more fuel for the air-breathing engine, and the lower ramjet take-over speed means the weapons needs less propellant for the booster rocket, the agency says. 

“The combination of these effects allows ram-RDEs to have significantly longer ranges than conventional ramjets, which enables their employment at standoff ranges,” DARPA says. 

DARPA Aims Gambit Missile Project At Fourth-Gen Fighters

Steve Trimble August 11, 2022

Rotating detonation engines are now being tested on tactical missiles.

Credit: Air Force Research Laboratory

A new, DARPA-funded program is intended to provide a long-range strike missile for fourth-generation fighters, leveraging the potential size and fuel efficiency advantages of rotating detonation engine (RDE) technology. 

DARPA unveiled the Gambit program in a July 20 special notice advertising a proposer’s day event on Aug. 16 for a 42-month effort to design and demonstrate the ramjet-RDE-powered, long-range missile concept. 

A week before the scheduled proposer’s day, DARPA has published a draft version of a broad agency announcement that provides new details on how such a weapon could be used in operations. 

The agency’s document explains how a ram-RDE propulsion system offers advantages over high-speed missiles powered by ramjets or turbines. 

“Given the limitations of existing propulsion technologies, Gambit is focused on developing ram-RDEs as a new class of propulsion to enable standoff strike of time-critical targets from 4th generation fighters at campaign scale,” the DARPA document says. 

Turbines, ramjets and RDEs all burn a mixture of fuel and air in a combustion chamber, but the latter does so in a completely different way. 

In a ramjet or turbine, the fuel-air mixture is combusted at a constant pressure in a process known as deflagration.  

In an RDE, the mixture is burned in an annular combustion chamber in a rotating wave of high-speed detonation at a constant volume. 

“These constant-volume detonations make ram-RDE combustors more compact and operable at speeds beginning much lower than conventional ramjets,” DARPA says. 

The more compact size of a ram-RDE combustor allows the missile to carry more fuel for the air-breathing engine, and the lower ramjet take-over speed means the weapons needs less propellant for the booster rocket, the agency says. 

“The combination of these effects allows ram-RDEs to have significantly longer ranges than conventional ramjets, which enables their employment at standoff ranges,” DARPA says. 

DARPA plans to select two companies to deliver conceptual and preliminary designs for a ram-RDE-powered missile, plus test the combustor and inlet within 18 months. A single company will then be selected to complete a critical design review, fabricate a demonstration missile and test the missile.

[넷서치]

참고로 detonation이란 flamefront의 propagation이 초음속인 연소과정을 말합니다. 그 자체로 상당한 효율 향상을 불러올 수 있어 DARPA 같은 국가 연구기관들을 비롯하여 GE나 RR 같은 사기업들도 미래 가스터빈 연소기 적용을 위해 연구 중이죠.

[백선호]

추가 설명 감사합니다. ^^

[만국]

RDE 엔진 기술 선도국가 중 하나가 의외로 일본이더군요. 작년에 세계최초로 실제 로켓으로 500N급 RDE 엔진 연소 시험도 성공했고 최근에는 RDE 엔진으로 제트모드 → 로켓모드 → 제트모드 연속 전환 시험에도 처음으로 성공했다고 합니다. JAXA 로드맵에 따르면 2025년까지 10kN급 만들어 지구 궤도에 투입하고 향후 개발되는 100kN급 RDE를 다발로 묶어 기존 우주 로켓엔진을 대체한다는 구상을 하고 있기도 하고요.