Method for designing structure of low-cost test combustion chamber with reliable thermal protection

Abstract

The invention discloses a method for designing a structure of a low-cost test combustion chamber with reliable thermal protection. The combustion chamber comprises a body barrel segment, a connecting flange, a nozzle part, a connecting bolt and a measuring filler neck part. The combustion chamber adopts a capacitive type structure; the body barrel segment is made of a pure copper material with a high thermal conductivity; and the nozzle part is made from a copper-infiltrated tungsten material. In the invention, a thermal analysis aided design method is required to be used firstly, which needs to establish a computation mode and a computing method at first and then perform an iterative design process of the structural design and the thermal analysis. The computation mode adopts an unsteady thermal-dimensional heat conducting differential equation and the computed heat exchange mainly comprises heat convection from the gas to the chamber wall and the radiant heat exchange, the heat conduction in the chamber wall, the convection from the chamber wall to the outside and the radiant heat exchange. The thermal analysis aided design method comprises a global computing analysis and a local correcting and computing analysis. The method can minimize the materials used under the condition that the combustion chamber has the reliable thermal protection and greatly reduce the cost.

Description

【Technical field】 [0001] The present invention relates to a method for designing a combustor structure with reliable thermal protection and low cost for short-time tests. The invention is especially used for the design method of the combustion chamber applied to the test of the liquid rocket engine. 【Background technique】 [0002] In the development process of the rocket engine thrust chamber, especially the injector as the main component of the thrust chamber, a large number of short-term combustion test studies are required; in addition, in the heat transfer characteristics or heat flow measurement of the thrust chamber In the test conducted for research, a short-term combustion test study must also be carried out. [0003] In the thrust chamber test research, two types of combustor structures are generally used, namely heat capacity type and water cooling type. In order to obtain the most extensive data in the test, carry out more comprehensive test research, and save c...

AI Technical Summary

Problems solved by technology

Generally, the heat capacity structure in the field of rocket engines is divided into two forms: 1. Using ablation-resistant materials such as tungsten-infiltrated copper, due to the ablation resistance of materials, it is widely used in the field of rocket engines, especially as the throat of the nozzle part of the thrust chamber Lining, but the physical properties of tungsten copper infiltrated materials are unstable, with large deviation, and the material is easy to be oxidized. In the test, the temperature measurement of the wall surface of the combustion chamber is often required, so the measurement accuracy cannot be reliable, and the tungsten copper infiltrated machining is difficult. , high cost, and the application in the cylinder section is not ideal

2. Using materials with high thermal conductivity such as pure copper, due to the good physical stability of the continuous test of copper, the accuracy of wall temperature measurement can be reliably guaranteed, and the cost of copper is lower than that of tungsten infiltrated copper materials; but due to the resistance of copper materials The disadvantage of low thermal limit is that the wall of the combustion chamber is generally designed to be very thick to meet the needs of the test time, and the measurement or ignition device is generally installed inside the copper body, which will inevitably affect the local heating effect of the copper. If the design is unreasonable Likely to cause local overheating and ablation

These two methods have been applied, but the cost of these two materials is not low, especially when the outer diameter of the part is larger, with the increase of the radial dimension, the material volume will grow faster and the cost will increase. The faster the increase; however, if too few materials are used or the local design is unreasonable, the heat capacity of the combustion chamber will be insufficient or the heat transfer effect will be poor, and ablation will easily occur, resulting in unreliable thermal protection

Therefore, there is a need for a specific method to design a combustion chamber with both reliable thermal protection and the lowest cost. This design method has not been reported yet.

Images