Recovery enthalpy calibration test piece and wind tunnel thermal assessment method

Abstract

The invention provides a recovery enthalpy calibration test piece and a wind tunnel thermal assessment test method. The method comprises the following steps: designing the recovery enthalpy calibration test piece and acquiring a back temperature change curve of a concerned part of the test piece; acquiring a change curve of hot-wall heat flow on the surface of the test piece along with wall enthalpy, and acquiring a hot-wall heat flow calculation formula through linear fitting; acquiring an enthalpy drop influence quantity delta H, which satisfies the equation that H=H-h<r>, caused by water cooling and heat absorption of a spray pipe according to a difference between the actual recovery enthalpy of the surface of the test piece and the designed surface recovery enthalpy H; acquiring a newtest enthalpy value newH, which satisfies the equation that newH=2H-h<r>; and adjusting the total enthalpy of airflow at the inlet of the spray pipe to a new test enthalpy value newH, and carrying outa wind tunnel heating test to ensure that the actual recovery enthalpy of the surface of the assessed piece reaches a design state. The enthalpy drop influence quantity caused by water cooling and heat absorption of the spray pipe is evaluated through the test piece, and the test state of formal assessment is designed according to the enthalpy drop influence quantity, so a thermal protection system of an aircraft is assessed truly and effectively.

Description

technical field [0001] The invention relates to a method for conducting a thermal assessment test in a wind tunnel by using an electric arc, and belongs to the technical field of thermal assessment experiments. Background technique [0002] The development of hypersonic vehicles must first solve the problem of heat protection. At present, in the research of structural thermal protection systems, the selection and assessment of materials mostly rely on arc wind tunnels. Therefore, it is necessary to formulate a reasonable test state according to the thermal environment of the aircraft to be assessed to achieve accurate material level assessment. It can be said that the arc wind tunnel thermal environment test is a key test to determine whether a material can "go to the sky". [0003] For large-area materials of aircraft, a flat-plate thermal assessment test is usually used. The high-temperature airflow generated by the arc heater is sprayed out through the lead-out section, ...

AI Technical Summary

Problems solved by technology

Since the actual thermal assessment test piece usually cannot be reheated repeatedly, and the processing cycle is long and expensive, once the thermal assessment test fails to achieve the purpose, it will cause serious waste of time and money. Before the formal thermal assessment test, it is necessary to carefully evaluate the water cooling heat absorption of the nozzle The influence of enthalpy drop is used to guide the design of the formal thermal assessment test state

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