Preliminary research on spray nozzle atomization characteristics in icing wind tunnel environment

The icing cloud inside the icing wind tunnel test section is generated by the Spray Bar System (SBS)which is located at the wind tunnel settling chamber.The icing conditions such as the icing cloud liquid water content (LWC)and water droplet size (MVD)are determined by the performance of the spray nozzle of performance on SBS.The enviromental parameters of the icing wind tunnel operation such as the pressure,temperature,wind speed and diameter of liquid droplet can change the final atomization characteristics in the test section.In the 0.3m× 0.2m icing wind tunnel with low pressure spray nozzle testing platform,we used Phase Doppler Interferometer(PDI)to measure the droplet evaporation rate and spray nozzle performance enve-lope in different icing wind tunnel operation environments.The experimental results show that:the icing wind tunnel flow condition can change the MVD when the liquid droplets fly into the test section through the contraction section;when the wind speed,the temperature and Reynold number of liquid droplet increase,the evaporation rate of droplet will also increase;the ambient pressure has an indispensable influence on the MVD and spray nozzle performance envelope;as the ambient pressure reduces,the spray nozzle flow mass-MVD envelope is narrowed down,but the spray nozzle water flow mass is hardly influenced.These experimental results can be used in the icing wind tunnel for icing cloud simulation and uniformity debugging.