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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 55957 (45)
- University: Sharif University of Technology
- Department: Aerospace Engineering
- Advisor(s): Morad, Mohammad Reza
- Abstract:
- The electrospray technique involves the production of small charged droplets through the application of electrohydrodynamic forces. Under well-defined operating conditions, multiple flow modes can be observed, among which the stable jet-cone mode has received significant attention from the research community. This mode is desirable due to its uniform droplet diameter, reduction in droplet rebound when impacting hot surfaces, and potential for utilizing two-phase heat transfer for cooling purposes. In this study, a comprehensive experimental investigation was conducted to evaluate the cooling of hot surfaces through the use of electrospray in the steady cone-jet mode. The fundamental principles and characteristics of electrospray systems were thoroughly studied and analyzed through a series of experiments designed to examine the underlying phenomena related to electrohydrodynamic flow and two-phase cooling. The critical heat flux was analyzed in terms of its sensitivity to various parameters, including geometrical variables and control variables. Water was used as a novel cooling fluid, and its suitability for this application was explored. The stability region of the steady cone-jet mode was determined through the analysis of the electric current of the jet and examination of its profile through photography. The sensitivity of the critical heat flux to volumetric flow rate, electric voltage, and volume fraction of water was studied in detail. The results of the study demonstrate that the addition of 70% volume fraction of deionized water to pure ethanol can result in an appreciable increase in the critical heat flux, up to 170%. Furthermore, the designed electrospray system was found to be more efficient than existing solutions, with smaller droplet diameters, improved reliability, and lower operating costs. These findings contribute to a deeper understanding of the electrospray technique and its potential for cooling hot surfaces in various applications
- Keywords:
- Electrospray ; Heat Cooling ; Critical Heat Flux ; Electrohydrodynamic ; Cone-Jet
- محتواي کتاب
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- مقدمه
- مفاهیم اولیه
- کارهای پیشین
- چیدمان آزمایشگاهی و متدولوژی تجربی
- نتایج
- نتیجهگیری
- مراجع
- واژهنامه