# Investigation of temperature rise characteristics in the pre-stage of a deflector jet servo valve

## TL;DR

This study models and validates temperature rise in a deflector jet servo valve's pre-stage to improve control accuracy in aerospace systems.

## Contribution

A thermodynamic model using the control volume method is developed to predict heat generation and temperature rise in the pre-stage of deflector jet servo valves.

## Key findings

- A thermodynamic model accurately predicts temperature distribution with less than 0.76°C error.
- Temperature variations in the pre-stage significantly affect control accuracy of the servo valve.
- A temperature-controlled test rig validated the model's predictions under varying operating conditions.

## Abstract

In aerospace equipment, the deflector jet servo valve is a high-end core control component of electro-hydraulic servo systems. The pre-stage is crucial because of the compact structure and complex jet morphology. Temperature variations can significantly impair the valve’s control accuracy. To address the mechanism of heat generation and temperature prediction inside the pre-stage, a thermodynamic model of the pre-stage is developed using the control volume method to predict heat generation and temperature rise under varying operating conditions. This model enables prediction of temperature distribution across various chambers and the casing based on specified deflector displacements. A dedicated temperature-controlled test rig is established to measure the temperature distribution on the servo valve casing. Comparison of simulation results with experimental data validated the accuracy of the proposed model, and the temperature distribution predicted by the model has less than 0.76 °C error compared to the experiment. This study provides a theoretical basis for performance enhancement and structural optimization of deflector jet servo valves.