Recently, Galactic Energy has completed the assemble and delivery ,and even passed the cold test of the pin type injector thrust chamber, which is the key component of the Welkin liquid oxygen/kerosene engine. This will be the first 50t liquid oxygen/kerosene pin type injector in China, the products will be delivered for final assembly, and the fire test will be carried out recently, to check the design scheme, as well as to get the the combustion performance of the thrust chamber.
PALLAS-1 an reuseble liquid middle-sized carrier rocket, which is independently designed by Galactic Energy. The first stage is composed of 7 Welkin variable thrust oxygen/kerosene engine, and the pin type injector is the technical key of variable thrust technology.
A typical liquid rocket engine injector consists of a large number of independent injection units distributed on the head panel of the thrust chamber. These injection units are usually of direct current strike or coaxial centrifugal type. The pin type injector has unique geometric structure and injection characteristics.
Pin type injector will be the entire injector deep into the combustion chamber, the fuel flows through the lateral flow channel of the center pin (the annular gap between the injection head and the pin sleeve) into the combustion chamber, forming an annular liquid film along the axial flow, so that it reaches the impact point with the same circumferential velocity. The oxidant flows through the sleeve of the pin and converts it into a uniform radial flow from the inner surface of the pin head, which collides with the axial flow fuel at 90 degrees,thus finally mixing and atomizing.
Pin type injectors offer excellent combustion stability, eliminating the need for such devices as sound chambers or baffles, simplifying thrust chamber construction, improving reliability and reducing manufacture costs.
The simplicity of the structure makes the pin injector suitable for low cost engines. A complete pin-pin injector can have as few as five parts, and by changing two simple parts, the injector's performance can be easily adjusted and optimized. Most parts of the pin injector work at good ambient temperatures, allowing it to be machined and welded with ordinary stainless steel, significantly reducing the cost of engine development and certification.
In the future, we will carry out related tests of the Welkin liquid oxygen/kerosene engine, and launch the full system test within this year, striving to build the world's second reusable liquid oxygen/kerosene engine and the first reusable liquid oxygen/kerosene engine in China after the SpaceX Merlin engine.