China reveals hypersonic scramjet developments and plans

China has revealed the first known images of an indigenous scramjet test that it says was successfully conducted at speeds up to Mach 7 and altitudes up to 30 km, in December 2015.

Credit: National Natural Science Foundation of China.

Studies of a folding-wing hypersonic boost-glide vehicle designed for deployment from a launcher at Mach 5 and 30-km altitude show dramatic changes in the center of pressure on release. Credit: China Academy of Launch Vehicle Technology

Tests of a magneto-hydrodynamic heat shield system showed performance could be boosted by seeding the flow with potassium particles. Credit: College of Aerospace Science and Engineering

Ground tests of a hydrogen-fueled continuous-rotating detonation ramjet at Mach 4.5 and simulated 18.5-km altitude indicated positive thrust was obtained. Credit: National University of Defense Technology

China will test a prototype combined-cycle hypersonic engine later this year that they hope will pave the way for the first demonstration flight of a full-scale propulsion system by 2025. If successful, the engine could be the first of its type in the world to power a hypersonic vehicle or the first stage of a two-stage-to-orbit spaceplane. Combined-cycle systems have long been studied as a potential means to access to space and long-range hypersonic vehicles.

Chinese Academy of Sciences professor Lihong Chen said: “We also developed a low cost near-space science and technology flight test platform. The first flight test was successfully carried out, and key issues of the scramjet were demonstrated at Mach 3.5-7 and at altitudes of 15-30 km [9-18 mi.].” Offering no further details, Chen says the flight test was targeted at fundamental research under a program that she likened to the Australian-U.S. Hypersonic International Flight Research Experimentation (HIFiRE) effort.

Zhang Yong, a CASTC engineer, claimed that China will master the spaceplane’s technologies in the next three to five years, and a full-scale spaceplane would then enter service by 2030.

Lihong Chen had written a Feb 2016, paper in Acta Mechanica Sinica – Engine performance analysis and optimization of a dual-mode scramjet with varied inlet conditions.

A dual-mode scramjet can operate in a wide range of flight conditions. Higher thrust can be generated by adopting suitable combustion modes. Based on the net thrust, an analysis and preliminary optimal design of a kerosene-fueled parameterized dual-mode scramjet at a crucial flight Mach number of 6 were investigated by using a modified quasi-one-dimensional method and simulated annealing strategy. Engine structure and heat release distributions, affecting the engine thrust, were chosen as analytical parameters for varied inlet conditions (isolator entrance Mach number: 1.5–3.5). Results show that different optimal heat release distributions and structural conditions can be obtained at five different inlet conditions. The highest net thrust of the parameterized dual-mode engine can be achieved by a subsonic combustion mode at an isolator entrance Mach number of 2.5. Additionally, the effects of heat release and scramjet structure on net thrust have been discussed. The present results and the developed analytical method can provide guidance for the design and optimization of high-performance dual-mode scramjets.