Optimization of Process Parameters of Composite Wicked Heat Pipe

. Heat pipe is used to extract heat generated from a surface and applicable to cooling of the many components. Some of the main applications of heat pipes are space crafts, computer systems, permafrost cooling, heat exchangers and thermal storage sub systems. In this work, an experiment will be carried out with an indirect heat composite pipe located with different orientation, heat input and mass flow. Thermal resistance, heat transfer coefficient and thermal efficiency are determined, which are applicable for laptop cooling and solar heating. Heat input 25 to 150 watts, with orientation angles 0, 30, 45, 90 degrees, mass flow rate are 0.01kg/sec, 0.02kg/sec and 0.03kg/sec are considered.


Introduction
A heat pipe is a closed system, usually a simple cylindrical tube sealed on both sides and partially filled with a working fluid that transfers heat in the form of latent heat of evaporation.Container, wick structure and small amount of working fluid in liquid state are the components of Heat pipe.The heat pipe is divided into three parts: the evaporator section, the adiabatic section and the condenser section.Now a day's heat pipes are extensively as a heat transmission device because of the following advantages like simplicity of design, exceptional flexibility, accessibility of control and the ability to transport heat at high speed over a considerable distance with an extremely small temperature difference, as well as the absence of the need for external pumping work.
Thermal performance of Nano fluid Filled and Nanoparticles Coated Mesh Wick Heat Pipes was investigated by Naveen Kumar Gupta [1,10.16] in 2018.The improvement in thermal execution of work wick heat pipe utilizing TiO2/H2O nano liquid as working liquid for various power input were examined and results indicated most extreme 17.2% decrease in thermal obstruction.Heat pipe utilizing Tio2/H2O nano liquid as working liquid shows higher thermal execution when contrasted with water.Roberto bubbico [2,9] et al 2018 analyzed of latent Temperature control frameworks utilizing stage change materials for application to auxiliary Batteries cooling.Analysis of thermal conduct of stage change materials (PCMs) used to chill off thermal metal surface was conveyed.CFD model composite material (PCM + strong froth) was created which permitted to anticipate the temperature pattern with in framework under various limit conditions.Theoretical model is really fit for foreseeing temperature pattern with great degree of estimate.Saurab B. Raut [3,11.17]studied the effect of various thermal contributions on the operation of wick heat pipes with various screen layers using water and CuO as working fluids.Mohammed T.Ababneh1 [4,18] et al 2018 worked on Hybrid Constant Conductance Heat Pipes and found High-Heat Flux (>50 W/cm2).Two crossover thermal propulsion heat and power plants were created and tested.Many times better thermal drive capability than standard hub groove CCHP design with smelling aluminum salts.Heat pipes work efficiently and can be used in many high thermal motion applications.Mehdi Famouri [5,19] et al. 2016.Conducted a transitional study of round and hollow heat pipes considering the distinctive wick structures.The thermal characteristics of the sections and hybrid wick structures were evaluated and matched with each other.The results show a significant increase in the temperature angle due to the use of a half-blood wick in both transient and continuous mode.
Ashvinirana [6,20] et al. (2014) conducted experiments with heat pipes with nanofluids as working fluids.Their results show improved thermal performance, heat transfer limit, and reduced thermal noise when using nanofluid than when using base fluid, and the thermal performance of sintered wick heat pipe is superior to anything that works with wick heat pipe.W.N.Septiadi [7] et al (2013) did Characterization of screen work wick heat pipe with Nano liquid as inactive cooling system.The utilization of nano liquid as working liquid cause's slender sedimentation on screen work wick covering diminishes pore size of work which could influence fine execution.Xianming Dai [8,21] et al 2011 did characterization of Hybrid mischievous copper heat pipe .A tale scale crossover wick was created in this examination to improve compelling thermal conductivity heat transition of level heat pipes.Experimental results show that powerful thermal conductivity can move toward 12,270 w/m k which in excess multiple times superior to unadulterated copper at application 91.3 heat input.Test study on sintered copper heat pipe with two distinctive working liquids to x specific ethanol and unadulterated water which is finished by R.Obaid 2011.In his examination he had considered conduct of heat pipe set in even by fluctuating heat inputs and presumed that presentation heat pipe with water as working liquid is more effective than ethanol as working liquid when both worked at same conditions.Vesion (2004) contemplated exploratory estimations heat and mass exchange in heat pipe wicks and saw heat input expands thermal obstruction going to diminish.Experimentation on impact thickness wick structure on heat move execution of heat pipe done by Hanlon, (2009).A speculative assessment has been done with numerical model results are differentiated and exploratory characteristics.He had contemplated that more thin is wick structure more is glow move execution.Authors [12][13][14][15] applied Taguchi method for optimization various processing parameters.

Objectives
The main objective of the experiment is to determine the thermal resistance, heat transfer coefficient and thermal efficiency which is applicable for laptop cooling and solar heating.Given heat input is 25 to 150 watts with orientation angle varying from 0, 30, 45, 60, 90 degrees and mass flow rates 0.01kg/sec, 0.02kg/sec, 0.03kg/sec.
• To enhance the heat transfer rate by using composite wick heat pipe.
• To find out the effect of heat pipe process parameters on the thermal performance of composite wicked heat pipe having Methanol as working fluid.• To optimize the heat transfer rate experimentally.
• To analyze Thermal Performance of heat pipe.
• To study the effect of composite wick structure on heat pipe performance.

Methodology
Experimental investigation on composite wicked heat pipe will be carried out for particular mass flow rate and particular angle orientation for all the input ranging from 25W to 150W.Similar investigations are done for all the flow rates and for all the orientations s shown tables 5.1 to 5.9.At the moment of heat supply to the evaporative section of the heat pipe (Fig. 1 and Fig. 2), the working fluid disintegrates.In thermodynamics, a change in pressure is directly related to a change in temperature.Thus, at a slightly higher temperature and pressure in the evaporator segment, it creates a pressure angle that directs the vapors towards the colder sections of the heat pipe.As smoke collects on the baffles of the heat pipes, the idle heat of vaporization is transferred to the condenser.The capillary wick at that point moves the condensate back to the evaporator area.This closed circle is a ceaseless procedure as long as heat is being applied.The wick structure is a concerned factor since great structure brings about stable narrow pumping pressure and also helps in keeping up the circulation of the liquid against the fluid and fume stream losses, and against antagonistic body forces, for example, gravity.The scheme of the experiment with a heat pipe is shown in fig. 3. The efficiency of the heat pipe is increased in all three parameters: heat input, inclination angle and flow rate.The rate of efficiency improvement is determined by the higher flow rate compared to the heat input and slope.As the flow rate increases, the amount of heat absorbed in the condenser section increases due to the high heat transfer coefficient of the water used as the cooling medium in the condenser.The optimal operating parameters (table 5.10) of the heat pipe can be found as a result of the experiments carried out, and their values are displayed in tables 5.1-5.9 by implementing the Taguchi method.Mass flow rate-0.01kg/sec, Angle-45° Mass flow rate-0.02kg/sec, Angle-15° Mass flow rate-0.02kg/sec, Angle-30° Mass flow rate-0.03kg/sec, Angle-15° Mass flow rate-0.03kg/sec, Angle-30°

Taguchi analysis for Optimization of Composite Wicked Heat Pipe
The goal is to decide the fundamental impacts of the working parameters of heat pipe, to play out the Analysis of variance (ANOVA) and to build up the ideal conditions dependent on the Taguchi method.Here is the optimization using Taguchi analysis: Table 5.11 and 5.12 shows the response and signal to noise ratio and means respectively and also explained in plots Fig. 5 and 6.

Conclusion
The results obtained table 5.10 that maximum heat transfer coefficient 149.4 W/m2-K is obtained for heat input 75watts, 30o of inclination and mass flow rate of 0.02kg/sec.Similarly maximum thermal efficiency of heat pipe obtained is 66% for 150W heat input, 15oinclination and mass flow rate of 0.03kg/sec.Table 6 Contribution of Efficiency, Thermal Efficiency and Heat transfer coefficient in performance of heat pipe From Taguchi analysis it is clear that, the contribution of all operating parameters (heat supply, angle of inclination and flow rate) to the operation of the heat pipe is equally important(Table 6).

Table 5 .
11 Response Table for Signal to Noise Ratios Table 5.12 Response Table for Means.Fig.5 Plot for SN Ratios Fig. 6 Plot for Means