As an advanced method for initiating detonation, shock-wave focusing (SWF) can do so directly without a separate igniter, and the distance of focusing initiation is much smaller than that of the deflagration-to-detonation transition, thereby greatly improving the performance of detonation engines. In this paper, the process of SWF detonation initiation with decane as the fuel is simulated, and it is found that the energy in the focusing region is high enough to initiate detonation directly. The total temperature and pressure of the incident flow are changed to study how the inlet parameters influence SWF. It is found that the total pressure of the incoming flow affects the SWF considerably whereas the influence of the total temperature can be ignored. The experimental results show that a kerosene–air detonation can be initiated successfully by SWF, thereby verifying the feasibility of SWF detonation with no pre-combustion chamber or igniter. The simulation and experimental results show that SWF detonation initiation has considerable advantages and potential.

A shock wave focusing initiation engine was assembled and tested in an experimental program. The effective pyrolysis rate of the pre-combustor was evaluated over a range of supplementary fuel ratio in this paper. Results highlight two operational modes of the resonant cavity: (1) pulsating combustion mode, (2) stable combustion mode. The appearance of the two combustion modes is jointly affected by the flow and the structural characteristic value of the combustion chamber. This paper uses images, time-frequency analysis, and nonlinear time series analysis methods to identify and distinguish these two combustion modes. It is believed that the interaction between the combustion chamber and the supply plenum is the probable reason for different combustion modes. The experiment has found that structural parameters and import flow parameters have an impact on the initiation of the combustion chamber. Increasing the injection pressure can appropriately broaden the fuel-rich boundary of initiation. Low equivalence ratio and high injection pressure can also appropriately increase the combustion working frequency in a small range. From the perspective of pressure utilization, under the premise of ensuring successful initiation, injection pressure should not be too high.