Zhou Changsheng

A Couple Approach for a Conjugate Heat Transfer Investigation of the Shape-Change Effects in a Composite Nozzle

To address the conjugate heat transfer problem in complex geometries, a coupling approach based on the local coordinate transformation is developed to evaluate the common wall temperature on non-orthogonal solid–fluid interfaces. The proposed coupling approach is validated and then used to investigate the erosion-induced shape change effects in a composite nozzle. The changes of flow field are evident in terms of the Mach number, temperature, and pressure, especially in the vicinity of erosion steps. The comparison of the wall pressure distribution indicates that the nozzle thrust performance degrades after erosion.

Application of Time-Temperature Superposition Principle to Non-Linear Deformation in Composite Propellant

A series of constant-rate tensile tests and relaxation tests were conducted to assess the mechanical properties of the hydroxy-terminated polybutadiene (HTPB) propellant. The relaxation modulus master curve was acquired using relaxation tests at the linear viscoelastic segment, and stress-reduced time master curves at different strain levels were established to determine whether the time–temperature superposition principle (TTSP) could be used to assess the non-linear mechanical property of the HTPB propellant. Results showed that the mechanical properties of HTPB propellant strongly depend on temperature; the extent of this dependence is enhanced with decrease in temperature, and the TTSP can be used in non-linear segments. With the application of the TTSP, the ultimate strength and the stress–strain curves of constant-rate tensile tests can be predicted at any temperature and strain rate, and the predicted σ–e responses matched the test results closely, but led to some errors at high temperatures, this ...

Combustion modeling of unsteady reacting swirling flow in solid fuel ramjet

The differences between finite-rate and eddy- dissipation models for simulating unsteady reacting swirling flow through solid-fuel ramjet engine are investigated. An in-house code has been developed to solve governing equations of compressible flow field with chemical reactions. The code is verified, validated, and then used to perform unsteady simulations on solid-fuel ramjet engine with high-density polyethylene. The results showed that both models are act similar, however, finite-rate model is preferred in such combustors with non-premixed flames (diffusion flames) over eddy-dissipation model.

Effect of using swirl on reacting flows in solid-fuel ramjet

In this paper, the influence of swirl on solid fuel regression rate and combustion phenomena in a solid fuel ramjet has been investigated numerically. Firstly, an in-house code has been developed to solve axisymmetric Reynolds-averaged Navier-Stokes equations of the unsteady turbulent swirling compressible flow field with chemical reactions. Secondly, unsteady simulations are carried out for unsteady reacting turbulent flows with and without swirl in a solid fuel ramjet using high-density polyethylene (HDPE) solid fuel. Then, the computational results are analyzed and discussed. It is found that the presence of swirl is more effective in enhancing the regression rate and the turbulent mixing throughout the ramjet. Moreover, increase swirl number increases the heat and mass transport at the fuel surface and hence increases the regression rate.