دراسة تأثير الجريان المتميع (غاز – صلب) على أداء الانبوب الحراري

Study The Effect of (Gas-Solid) Fluidized Flow on Heat Pipe Performance

   This work presents an experimental and numerical study to investigate enhancement the heat transfer values to heat pipe by using fluidize bed. Using cement fly ash as a fluidize material that was heated to simulate cement factory chimney, the air interred to manufacturing model and heated by electrical heater. Air interring with superficial velocity (0.8739,1.1236, and 1.377) m/s. The cement fly ash particle putting in air flows way at evaporator part with different height (2.5,5,7.5and10) cm.
The experimental system (test rig) which includes: flowmeters, thermocouples, U-tube manometer, valves, heat pipes, wooden box, connected airlines, and cyclone, was fabricated to calculate enhancement in heat pipes heat gain. Manufacturing three wick heat pipes was the first step the outer and inner pipe diameter was (22.25 and 19.80) mm respectively, five stainless steel layers fixed inside each pipe. Distilled water was used as working fluid with amount (65.5) ml, and all heat pipes was arranging horizontally in test rig.
All the tests were carried out with a Reynolds number range (Re = 2400 – 318728) and uniform inlet velocity conditions, the experimental study also includes preparation of particles and measurement its properties such as density, thermal conductivity, and particles diameter. The flow rate, domain and heat pipes surface temperature and pressure drop, were measured.
ANSYS FLUENT bundle-(18) soft program was used to solve the governing differential equations in two and three dimensions to study the effect and focus on heat transfer improvement and particles behavior inside domain.
This study found that The maximum Nusselt number was (35.2) which is occurred at (Re = 318728), increasing Reynolds number from (2400 to 318728) gives increased in heat gain at heat pipes evaporator part by (72.5) %, also the results show that increase solid particle degreased porosity by (9%),also Increasing superficial velocity for (0.8739 to 1.337) m/s increased the heat gained at evaporator part to (21) % , The comparison between the experimental and numerical (Nusselt number) shows acceptable agreement, and the maximum and minimum differences were ±(18.6, 4) % respectively.