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An Experimental Evaluation of Thermal Conductivity of Colloidal Suspension of Carbon-Rich Fly Ash Microparticles and Diamond-Nano Powder (DNP) in Jet-A Fuel

MetadataDetails
Publication Date2025-07-01
JournalProceedings of the 
 International Conference on Fluid Flow, Heat and Mass Transfer
AuthorsAhmed Aboalhamayie
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  • The study investigates enhancing the thermal conductivity of Jet-A fuel using Carbon Fly Ash (CFA) and Diamond Nano Powder (DNP).
  • CFA, a byproduct of heavy fuel oil combustion, contains unburned carbon and inorganic oxides, possessing a porous structure.
  • DNP is used as a comparative material due to its high thermal conductivity.
  • A two-step process (surfactant addition and sonication) was used to stabilize colloidal suspensions.
  • A 3% CFA concentration in Jet-A fuel resulted in an 8% increase in thermal conductivity.
  • CFA’s porous structure and trace iron content contribute to the significant thermal enhancement.
  • The study highlights the potential of CFA as a cost-effective additive for improving fuel performance.
ParameterValueUnitContext
CFA Particle Size30”mAverage particle diameter
DNP Particle Size3-10nmAverage particle diameter
CFA True Density1.07g/cm3Material property
DNP True Density3.05-3.30g/cm3Material property
CFA Specific Surface Area (SSA)1.8m2/gSurface area available for interaction
DNP Specific Surface Area (SSA)~280m2/gSurface area available for interaction
Span 80 Surfactant Concentration3wt.%Stabilizing agent in Jet-A fuel
Sonication Power30%Ultrasonic bath power setting
Sonication Time45minutesDuration of ultrasonic treatment
Water Cooling Rate3liters/minuteCooling jacket flow rate
Baseline Jet-A Thermal Conductivity0.995W/m·°CThermal conductivity of pure Jet-A fuel
CFA (3 wt.%) Thermal Conductivity1.078W/m·°CThermal conductivity of Jet-A fuel with 3 wt.% CFA
DNP (2 wt.%) Thermal Conductivity1.015W/m·°CThermal conductivity of Jet-A fuel with 2 wt.% DNP
Temperature26.2°CTemperature shown on Voltmeter
Voltage Settings100, 120, 140VVoltage applied to the heater
Nano fuel layer thickness0.325mmThickness of the Nano fuel sample
  1. Preparation of Suspensions:
    • A 3 wt.% solution of Span 80 surfactant in Jet-A fuel was prepared using magnetic stirring for 30 minutes.
    • CFA or DNP particles were added to the surfactant solution and stirred for 10 minutes to form a homogeneous mixture.
    • The mixture was then sonicated in an ultrasonic bath at 30% power for 45 minutes.
  2. Stability Testing:
    • The stability of the colloidal suspensions was assessed using a custom-built apparatus with an IR laser and receiver.
    • Visual inspection using a flashlight was also employed to monitor particle settling.
  3. Thermal Conductivity Measurement:
    • A Hilton Ltd H470 thermal conductivity apparatus was used.
    • A thin layer (0.325 mm) of the Nano fuel sample was placed between a heater and a cooling jacket.
    • Cold water was circulated through the cooling jacket at a rate of 3 liters/minute.
    • Three different heat fluxes (voltages of 100V, 120V, and 140V) were applied.
    • Temperatures on both sides of the liquid sheet were measured using Type-K thermocouples.
    • Thermal conductivity was calculated using Fourier’s law of heat conduction.
    • Concentrations tested were 0.05%, 0.1%, 0.15%, 0.25%, 0.5%, 1%, 1.5%, 2%, and 3% by weight.
  • Fuel Additives: CFA and DNP can be used as additives to enhance the thermal properties of fuels, potentially improving engine efficiency and performance.
  • Heat Transfer Fluids: The colloidal suspensions could be used as heat transfer fluids in various applications, such as cooling systems and heat exchangers.
  • Heavy Oil Processing: CFA, as a byproduct of heavy oil combustion, can be repurposed and valorized as a functional additive.
  • Materials Science: The study provides insights into the behavior of micro and nanoparticles in liquid suspensions, relevant to the development of advanced materials.