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Investigation of Flow Inside the Pressure Swirl Atomizer

Kebriaee, Azadeh | 2012

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 43074 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Nouri Boroujerdi, Ali
  7. Abstract:
  8. In the present work, the behavior of flow inside the pressure-swirl atomizers (PSA) is studied by the numerical simulation. The pressure-swirl atomizer is widely used in many industrial applications such as fuel injection in gas turbine, internal combustion engine and liquid-fuel rocket, spray drying, spray in firing and agricultural nozzles.
    The flow simulation inside the injector (PSA) deals with many complicated considerations due to air core formation in the axial zone of the injector as well as high tangential and axial velocities in the swirl chamber. The two phase flow is modeled by level set methods in the pressure swirl atomizer. Moreover, the explicit algebraic Reynolds stress model is applied to simulate the turbulent flow in the injector. For the first time in this dissertation, the interface motion in a swirling flow is modeled by level set method. In this work, a novel numerical method has been proposed to solve the level set equation which leads to increase the accuracy of level set equation solution and to decrease the computational time compared to traditional methods. In addition, using the explicit algebraic Reynolds stress has increased the solution accuracy in the whole of the computational domain with modeling heterogeneous Reynolds stress components.
    The result of flow simulation inside Horvey’s injector as well as Rizk’s illustrate that the present numerical solution has enough ability to simulate the flow inside the pressure swirl atomizers. Comparing the simulation of laminar and turbulent regime flow also highlights the significance of the stability study inside the pressure-swirl atomizer. The primary studies are done about the stability problem in the swirling flow that it confirms the stability of the swirling flow is increased in high axial velocity. After studying the behavior of flow inside the pressure swirl atomizer, a modified design is innovated to improve the injector performance. To validate the improvement of novel design, the discharge coefficient, the cone angle of spray, and the thickness of film liquid are compared with the characteristics of the original injector. Findings show that the discharge coefficient is improved about 6% as well as the angle of liquid exit is increased about 5.6%, while the thickness of liquid film remains constant due to equipping a constant rod in the axial zone
  9. Keywords:
  10. Level Set Method ; Pressure-Swirl Injectors ; Explicit Algebraic Reynolds Stress Model ; Turbulent Boundary Layer Solution ; Swirl Flow Stability

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