Investigation on the suitability of conventional film hole under pulsed detonation incoming flow conditions

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-11-28 DOI:10.1016/j.ijthermalsci.2024.109570

Ji-Chen Li, Hui-Ren Zhu, Lin Ye, Long-Xi Zheng, Dao-En Zhou, Cun-Liang Liu

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引用次数: 0

Abstract

As a novel and efficient engine, the pulse detonation engine will increasingly demand advanced cooling technology. Film cooling, widely utilized in conventional aero engines, is also anticipated to be employed in pulse detonation engines. However, further investigation is required to assess the suitability of conventional film holes for pulse detonation engines. This study determines the cooling characteristics of a plate with a single film hole in a pulse detonation engine operating at a frequency of 30Hz through numerical calculations. The types of film holes considered include cylindrical, fan-shaped, laid-back, laid-back fan-shaped, and converging-slot holes, all of which have a diameter of 1 mm and an inclination angle of 30°. The single pulse detonation period is divided into stages: initiation and detonation wave propagation, gas exhaust, and refilling. During the initiation and detonation wave propagation stage, the film hole exhibits a significant backflow phenomenon, with the magnitude of gas backflow positively correlated with the outlet area of the film hole. Notably, the converging-slot hole experiences the least amount of gas backflow, with an exit area 33 % smaller than that of cylindrical holes and a corresponding 18 % reduction in backflow enthalpy. Throughout the initiation and detonation wave propagation stage, the backflow gas carries an enthalpy ranging from 0.43 J to 0.63 J into each individual film hole. In the gas exhaust stage, the blowing ratio increases over time as the mainstream pressure decreases, leading to a rapid decline in the film cooling effectiveness of the cylindrical and laid-back holes. The converging-slot holes have the largest film covering area, thus exhibiting the highest film cooling effectiveness, which is 53 % higher than that of the cylindrical hole. In the refilling stage, the mainstream temperature reaches the same level as the secondary flow temperature, rendering the consideration of the cooling characteristics of the film hole unnecessary. Under the conditions of this study, the converging-slot hole is found to be most suitable for cooling the pulse detonation engine.

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传统膜孔在脉冲爆轰来流条件下的适用性研究

脉冲爆震发动机作为一种新型高效发动机，对先进的冷却技术提出了越来越高的要求。在传统航空发动机中广泛应用的气膜冷却技术也有望在脉冲爆震发动机中得到应用。然而，需要进一步的研究来评估传统的膜孔对脉冲爆震发动机的适用性。本研究通过数值计算确定了频率为30Hz的脉冲爆震发动机单膜孔板的冷却特性。考虑的膜孔类型包括圆柱孔、扇形孔、悠闲孔、悠闲扇形孔和会聚槽孔，其直径均为1 mm，倾角为30°。单脉冲爆轰周期分为起爆爆波传播阶段、气体排出阶段和再填充阶段。在起爆波传播阶段，膜孔内出现了明显的回流现象，气体回流的大小与膜孔出口面积呈正相关。值得注意的是，聚缝孔的气体回流量最小，出口面积比圆柱孔小33%，回流焓相应降低18%。在整个起爆波传播阶段，回流气体带着0.43 ~ 0.63 J的焓进入每个膜孔。在排气阶段，随着主流压力的降低，吹气比随时间的增加，导致圆柱孔和斜孔的气膜冷却效果迅速下降。汇聚槽孔具有最大的膜覆盖面积，因此具有最高的膜冷却效果，比圆柱孔的膜冷却效果高53%。在充注阶段，主流温度达到与二次流温度相同的水平，无需考虑膜孔的冷却特性。在本研究条件下，发现聚缝孔最适合用于脉冲爆震发动机的冷却。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.