Tests of the JAPHAR dual mode ramjet engine

In 1997, ONERA and DLR decided to join their efforts on hypersonic air-breathing vehicles in the frame of the JAPHAR program. For this purpose, a vehicle demonstrator has been chosen as a guideline for the studies and a dual mode ramjet engine has then been designed for this vehicle. An experimental scramjet has been derived from it. A first tests campaign has been performed for simulated flight Mach number of 4.9, 5.8 and 7.5 [P. Novelli, W. Koschel, ISABE paper 99-7091, in: 14th Symp. ISABE, Florence, Italy, 1999; O. Dessornes, D. Scherrer, P. Novelli, ISABE paper 2001-1135, Bengalore, India] followed by complementary tests that consisted of weighing the test chamber. Finally, an additional test campaign was carried out in 2003 with a modified injection set-up and also with a calorimetry device that allowed to determine the combustion efficiency experimentally, which wasnʹt done before. In order to work as a dual mode ramjet, the combustion chamber has two injection stages. The first is mainly dedicated to supersonic combustion whereas the second allows to have a subsonic combustion with a thermal throat located near the chamber end. The main experimental results are discussed and comparisons with 3D Naviers–Stokes computation are also presented.