|
The Armstrong Siddeley, later Bristol Siddeley Gamma was a family of rocket engines used in British rocketry, including the Black Knight and Black Arrow launch vehicles. They burned kerosene fuel and hydrogen peroxide. Their construction was based on a common combustion chamber design, used either singly or in clusters of up to eight. They were developed by Armstrong-Siddeley in Coventry, which later became Bristol Siddeley in 1959, and finally Rolls-Royce in 1966. Engine static testing was carried out at High Down Rocket Test Site, near The Needles on the Isle of Wight ().〔(Black Knight Testing at The Needles )〕 (Spadeadam in Cumbria wasn't used for testing until Blue Streak, after Gamma). == Advantages of kerosene / peroxide engines == Use of kerosene / hydrogen peroxide engines has been a particularly British trait in rocket development, there being few comparable engines (such as the LR-40) from the USA. The combustion of kerosene with hydrogen peroxide is given by the formula : CH2 + 3H2O2 → CO2 + 4H2O where CH2 is the approximate formula of kerosene (see RP-1 for a discussion of kerosene rocket fuels). This compares with the combustion of kerosene and liquid oxygen (LOX) : CH2 + 1.5O2 → CO2 + H2O showing that the exhaust from kerosene / peroxide is predominantly water. This results in a very clean exhaust (second only to cryogenic LO2/LH2) and a distinctive clear flame.〔(【引用サイトリンク】url=http://members.aol.com/nicholashl/ukspace/blackarrow/blackarrow.htm ), The "levitation" picture, showing the R3 / Prospero launch lifting off on Gamma's invisibly transparent exhaust plume.〕 The low molecular mass of water also helps to increase rocket thrust performance. The oxidiser used with Gamma was 85% high-test peroxide (HTP), H2O2. Gamma used a silver-plated on nickel-gauze catalyst to first decompose the peroxide. For higher concentrations of H2O2 another catalyst would have been required, such as platinum. No ignition source was required since the very hot decomposed H2O2 is hypergolic (will spontaneously combust) with kerosene. Due to the high ratio (8:1) of the mass of H2O2 used compared to the kerosene, and also its superior heat characteristics, the H2O2 may also be used to regeneratively cool the engine nozzle before combustion. Any pre-combustion chamber used to power the pump turbines needs only to decompose H2O2 to provide the energy. This gives the efficiency advantages of closed cycle operation, without its usual major engineering problems. All of these characteristics lead to kerosene / hydrogen peroxide engines being simpler and more reliable to construct than other liquid propellant chemistries. Gamma had a remarkably reliable service record for a rocket engine. Of the 22 Black Knight and 4 Black Arrow launchers, involving 128 Gamma engines, there were no engine failures.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bristol Siddeley Gamma」の詳細全文を読む スポンサード リンク
|