燃烧室突扩扩压器外壳形式对扩压器性能影响的试验研究

通过自行设计的带有前置扩压器及盲孔火焰筒的二元对称直壁短突扩扩压器模型试验件,和八种扩压器外壳结构,着重探讨了扩压器外壳形式的改变对扩压器总性能的影响规律。通过大量的试验,得出一些重要结论,这些结论对实用型突扩扩压器的最佳设计将具有一定的指导意义。试验中测定了火焰筒头部区域的压力分布及前置扩压器中的沿程压力分布,为短突扩扩压器流场数值计算提供了必要的验证数据。

EXPERIMENTAL INVESTIGATION OF THE INFLUENCE OF DIFFUSER SHELL SHAPES ON PERFORMANCE OF DUMP DIFFUSERS IN COMBUSTOR

The overall performance of a two-dimensional symmetric straight-walled dump diffuser in combustor is investigated experimentally. The test model consists of a straight-walled pre-diffuser with fixed diffuser wall angle(2 = 12°) ,a semicircular head flame tube without holes, two throttles for varying flow split ratio(S)between upper and lower channels surrounding the flame tube, add eight different diffuser shells, The experiments were carried out under the conditions of Main =0.277 and S = l, and for each of the eight shells, the dump gap (D) was changed 4 times. The main purpose of the tests is to study the influence of the different shell shapes and dump gaps on the overall performance of the dump diffusers.The results show that their influence on the loss of total pressure of the diffuser is strong and the maximum loss occurs when the front wall of the shell is located in the pre-diffuser outlet section. However, the change of shell shapes has only small influence on optimal dump gap (for minimum loss of total pressure). In all the test cases, the optimal dump gaps are within D = 40mm and D = 50mm. The experiments also indicate that under certain operating conditions there exist low pressure areas around the head of the flame tube, The external static pressure in these areas can be lower than the pressure in the flame tube. Therefore, any holes in the areas should be placed with great care to avoid reversed flow.