Performance assessment of parabolic trough collector (ptc) by using three passes receiver for preheating the fuel oil under Iraq climate for different mass flow rates

An alternative design receiver of parabolic trough collector (PTC) has been discussed in the present study. The three passes design (3p) receiver made from copper and coated with selective black paint was studied and optimized experimentally. Mass flow rates were varied alongside number of days. The proposed design was compared with the PTC equipped with smooth receiver (SM). The aforementioned variations resulted in the experiments performed in September 2018. The 17th, 18th, 19th, and 20th, were chosen for the PTC with smooth receiver, while 25th , 26th, 27th, and 28th were for the receiver with three passes). The solar irradiances for these days were similar. The heat transfer fluid (HTF) was fuel oil. Mass flow rates of 2, 2.5, 3, 3.5 LPM were observed alongside change in number of days for the experiment. The results show that the PTC with three passes receiver achieved higher average thermal efficiency and average useful energy than the PTC with smooth receiver

Enhancement of heat transfer in six-start spirally corrugated tubes

The utilization of corrugation for improvement in heat transfer is increasingly becoming interesting recently due to its combined advantages such as extended surfaces, turbulators as well as roughness. This study employed the use of both numerical as well as experimental settings on the water flowing at lower Reynolds numbers in a corrugated tubes with spiral shape to evaluate the performance of heat in a newly designed corrugation style profile. The total performance of the heat for the corrugation tubes were determined and the mathematical information generated from both the Nusselt number and the factors of friction were equated with those of the experimentally generated outcome for both standard smooth as well as the corrugated tubes. Analysis of the dat generated revealed improvements in heat transfer ranges of (2.4–3.7) times those 0btained from the smooth tubes with significant increase in the friction factors of (1.7–2.3) times those of the smooth tubes. Based on the findings of study, it was concluded that for extended period and extensive range use, tubes with severity index values at 36.364×10–3 could produce better heat performance (1.8–3.4) at Reynolds numbers ranging from 100 to 1300. This was an indication that the geometric expression with spiral corrugation profile could significantly enhance the efficiency of heat transfer with significantly increased friction factors

Enhancement of heat transfer coefficient multi-metallic nanofluid with ANFIS modeling for thermophysical properties

Cu and Zn-water nanofluid is a suspension of the Cu and Zn nanoparticles with the size 50 nm in the water base fluid for different volume fractions to enhance its Thermophysical properties. The determination and measuring the enhancement of Thermophysical properties depends on many limitations. Nanoparticles were suspended in a base fluid to prepare a nanofluid. A coated transient hot wire apparatus was calibrated after the building of the all systems. The vibro-viscometer was used to measure the dynamic viscosity. The measured dynamic viscosity and thermal conductivity with all parameters affected on the measurements such as base fluids thermal conductivity, volume factions, and the temperatures of the base fluid were used as input to the Artificial Neural Fuzzy inference system to modeling both dynamic viscosity and thermal conductivity of the nanofluids. Then, the ANFIS modeling equations were used to calculate the enhancement in heat transfer coefficient using CFD software. The heat transfer coefficient was determined for flowing flow in a circular pipe at constant heat flux. It was found that the thermal conductivity of the nanofluid was highly affected by the volume fraction of nanoparticles. A comparison of the thermal conductivity ratio for different volume fractions was undertaken. The heat transfer coefficient of nanofluid was found to be higher than its base fluid. Comparisons of convective heat transfer coefficients for Cu and Zn nanofluids with the other correlation for the nanofluids heat transfer enhancement are presented. Moreover, the flow demonstrates anomalous enhancement in heat transfer nanofluids