CFD Fluent Analysis of Insulation Material, Optimum Insulation - vsrd ...

Available ONLINE www.vsrdjournals.comVSRD-MAP, Vol. 2 (3), 2012, 109-115R E V II E W A R T II C L ECFD Fluent Analysis of Insulation Material,Optimum Insulation Thickness of ReeferTruck : A Review1 Rahul Jain* and 2 RC GuptaABSTRACTThe main objective of this review paper is to analyze the best insulation material and optimum insulationthickness and velocity distribution using results obtained from computational fluid dynamics code FLUENT.Thus, paper discussed one of the crucial point of optimum thickness and best insulation material by CFDanalysis so that minimum losses from both economical and environment point of view.Keywords : Computational Fluid Dynamics Code Fluent, Reefer Van, RSM Model, k-ξ Model, WTSN, PCM.1. INTRODUCTIONThe reefer van are used to transport perishables foods such as Products, involved are candy, beverages, meat,poultry, fish, bakery and dairy products fruits and vegetables Ranging from life saving medicines to shipments,Pharmaceutical, tobacco products, personal care product, fine artwork, chemicals and engineering materials. Theinsulation material of reefer van may be polyurethane, polystyrene, plasterboard, polyisonurate, Bitumen etc.2. LITERATURE REVIEWMany theoretical and experimental studies have been done to understand the fundamental mechanisms of reefervan analysis and to understand the effect of various parameters on the performance of reefer van. Some of therecent studies on the insulation material, optimum insulation thickness and airflow pattern are reviewed as hereunder.M.S. Soylemez et al. (1999) [1] work on optimum insulation thickness of reefer van in which the effect of design____________________________1 Research Scholar, 2 Associate Professor, 1,2 Department of Mechanical Engineering, Jabalpur Engineering College, Jabalpur,Madhya Pradesh, INDIA. *Correspondence : rjain1465@gmail.com

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012parameters on the optimum insulation thickness are investigated for three test cities using an interactivecomputer code written in FORTRAN 77. Author made comparative study type of insulation in which Authorcompare cost and thermal conductivity in which thermal conductivity minimum for urethane (0.021W/m° C)and maximum for perlite (0.054 W/m° C) and cost minimum for fiberglass batt (38.14 $/m 3 )and maximum forfiberglass rigid (313.59 $/ m 3 ) lastly Author conclude that maximum savings takes place at 70mm of urethaneinsulation thickness and the optimum insulation decreases continuously with increasing thermal conductivitycost, except for this critical point and optimum insulation thickness inversely proportional to thermalconductivity cost of insulating material.W. R. da Veiga et al. (2002) [2] conduct experimental work in that thermocouples placed all around the vehiclesuch that one thermocouple was placed in the centre of the container and six other thermocouples were placedon the inner face of each of the container walls. Experimental work to determine heat transfer and Author findthat heat transfer coefficient varies from 5.15 W/m 2 k to 2.73 W/m 2 k and the average heat transfer coefficient is3.80 W/m 2 k.Tso et al. (2002) [3] used a commercial CFD program to model the effect of door openings on air temperaturewithin a refrigerated truck. A series of experiments to study the effect of door openings with air curtains andwith plastic strip curtains after two minutes the door was opened the average air temperatures was stated to haverisen from -10 to 14 ° C. The CFD simulation generally overestimated the temperature rise by 3 and 4 °c. AndAuthor concludes that the difference was due to the effect of condensing water vapour in the experimentalsituation.J. Moureh et al. (2002) [4] Compare experimental and numerical data in which Author used CFD to study theairflow by the code FLUENT on a reduced scale model (1:3.3) of a trailor. In their study, a second-momentclosure, the Reynolds stress model (RSM) and two equation turbulence models: the standard k-epsilon and arenormalization group (RNG), were tested and compared with experimental data. And Author find that thetemperature of compartment entrance is lowest and while behind body is highest and decreases in velocity frominlet section .Author also find that the wall jet separates from the ceiling at approximately 10 m in the case of anempty enclosure and 5 m in the loaded configuration. This separation splits the jet into two regions dominatedby two vortices of opposite circulation. Airflow separation due to Coanda effect.Stubbs et al. (2004) [5] developed numerical model for the length of time a foodstuff packed in an expandedpolystyrene box with a coolant could remain below 8 or 5 ° C. Author assumed that product will be deliveredwithin 24 hours of posting this was the only configuration that would maintain the product below 8° C whilesthe ambient temperature up to 30 ° C.Spence et al. (2004) [6] used a simple model to help in the initial development of an air cycle refrigeration unit.The unit developed was of the physical size and power as the conventional unit but in its unoptimised state itconsumed far more power .Author also show that there can be considerable differences in the refrigerationperformance of nominally similar transport refrigeration units when vehicles engines are idling, i.e. when thevehicles are moving slowly or stationary. The work was extended to look at the effect of air distribution.Qingshan Shan et al. (2005) [7] work on wireless temperature sensor network (WTSN) for refrigerated vehicle.110

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012At the time of driving driver don’t know what’s the inside temperature of refrigerated cabin. So to solve thisproblem sensors were placed at key positions and temperature display in front of driver by temperature sensor,so that driver notes the temperature at regular interval. Author concludes that the prototype of WTSNtechnologies and mathematical model are feasible, reliable and accurate. And future work still needed to furtherinvestigate into WTSN using artificial intelligence technologies for data management.S. J. James et al. (2006) [8] work on modeling of refrigerated van. With varying thickness from 25mm to 200mmAuthor plot a graph for heat extracted by refrigeration plant and Author find that with increase in thickness heatextracted continuously decreases and that only a small thickness of insulation greatly reduces the amount of heatto be extracted. Author also work on the rate of heat extract from the van, averaged over the periods when thevehicle is moving as the function of the number of stops the van makes. Author find one important differencebetween cold stores and refrigerated transport systems are that transport containers are not static and conditionsare affected by vehicle speed and orientation in relation to factors such as the sun. In their study Authorcalculate that the heat extracted from a poorly sealed van was 86% more than from a well-sealed van.Silvia Estrada et al. (2006) [9] in their experiment Author proposed that automatic air temperature monitoringequipment should be fitted to all refrigerated delivery vehicle. A thermocouple was placed in the centre of thecontainer and six other thermocouples were placed on the inner face of each of the container walls. The testswere conducted early in the morning to ensure a low ambient temperature. Author proposed that temperaturevariability was not related with effectiveness of the insulation nor the time required achieving complete coolingof the cargo space but temperature variability was correlated with the time required for the unit to recovertemperature control after a door opening and the difference between the maximum and minimum temperaturesreached during a door opening cycle. Author also finds that the temperature of compartment entrance is lowestand while behind body is highest. And lastly Heat flow in vertical direction is obvious quicker than in horizontaldirection.Alain Kondjoyan et al. (2006) [10] did comparative study of pork, loin, lamb, beef carcass. Author also didcomparative study between turbulence intensity conditions and air velocities. For turbulence intensity conditionvaries from 5% to 40% than air velocities varies from 2m/s to 4.4 m/s. Author also work on effect of differentfactors on average heat transfer coefficient values effect on air velocities. K-ξ models describe isotropicturbulences. K-ξ models valid for high turbulent Reynolds number. Author found that difficulty in generating aconstant temperature or constant heat flux on entire solid surface and the requirement of complete 3d flux ortemperature measurement. Author Compare experimental and numerical data and Author find that the decreasein velocity from the inlet section.Pieter Verboven et al. (2006) [11] did CFD analysis on sphere, potato, cheese, beetroot, orange, Mandarin,Tomato, apple and potato. So Author makes comparative analysis between velocity, porosity and Reynoldsnumber. In CFD analysis Author used K-ξ model. Author calculates contours of pressure (Pascal), velocity(m/s), turbulent kinetic energy (m 2 /s 2 ) and velocity vector. Author conclude that transport phenomenon arecomplicated by shape and size variation of many food products, the thermo physical properties of refrigeratedfoods and presence of turbulence during forced convection cooling. The direct CFD modeling of transportphenomenon in food bulks will help in design and optimization of refrigeration systems.111

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012Smale et al. (2006) [12] used Numerical modelling techniques to Prediction of airflow pattern. Experimentalresults can be successfully coupled with CFD to validate results and obtain most reliable evaluation of airflowpattern. Fluent analysis with the RSM turbulence model to predict the three dimensional airflow patterns withina refrigerated vehicle. CFD code Kameleon used to predict pressure and velocity distribution.Hongbo et al. (2006) [13] this paper is concerned with heat transfer and Phase Change Material (PCM).Calculated results were verified by experimental measured data. Author work for cryogenic range i.e. below -150°c. Numerical study has been conducted by using Computational Fluid Dynamics (CFD) code FLUENT.Author fined that larger biot no. is beneficial to heat transfer PCM and coolantDong Wang et al. (2006) [14] Analysis is conducted by comparing mass flow flux,static pressure coefficient overvan inlet and streamlines.Cooling performance is very sensitive.Prototype minivan with good agreement ofdesired cooling performance.Use FLUENT CFD code.Airflow distribution analysis.Francisco et al. (2006) [15] prepare computational fluid dynamic model of the heat and moisture transfer duringbeef chilling. Author made mathematical model after that using boundary conditions Author work on CFDmodeling .Author find relation between time and temperature are inversely proportional .lastly Author concludethat CFD predicted local temperature variation of up to 9° C and water activity variation of up to 9% around thebeef surface.Hui Jin et al. (2006) [16] done testing and modeling of under floor air supply plenums. Author done bothexperimental and CFD simulation and then Author made comparative study. In experimental study Author usetype T thermocouples and control system were installed to monitor air temperatures at the plenum inlet, floordiffusers, and selected locations inside the plenum and in CFD Author work on airflow pattern, air temperaturedistribution, and heat transfer from above and below plenum. Author used various governing equations andboundary conditions. Author work finely on airflow pattern, air velocity, temperatures at diffusers. Theirfindings are the magnitude of heat flux is associated with air velocity and air temperature, since convective heattransfer is a product of convective coefficient and temperature difference, Air velocity has its highest velocityand lowest temperature at inlet; obviously, heat flux decreases gradually after airflow enters and air velocity islow compared with inlet velocity. Lastly Author conclude the model was validated using experimental datacollected in a full scale plenum test facility and the computed air temperature, velocity ,and heat flux generatedagree well with the measured data.Teshome et al. (2006) [17] work on a zonal model in which direct and indirect approach of CFD to calculateairflow pattern. And Author fined that both clockwise and anticlockwise air circulation in zonal. Authorconcludes that MPLM (modified power-law model with variable k) is much better than PLMK (power-lawmodel with variable k).Zhijian Liu et al. (2007) [18] work on correlation between indoor air distribution and pollutants in naturalventilation. k-ξ model is used to determine the turbulent kinematic viscosity. The temperature and RH weretaken as the reference variable in the process of sampling. Author conclude that air distribution should bepredicted depending on CFD simulation before construction ,so as to avoiding the unreasonable designing andpoor air quality , mechanical ventilation should be employed when large population density. Author also fined112

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012that lower airflow velocity and unreasonable air distribution because of some vortexes existing.Fu-Yun Zhao et al. (2008) [19] perform the experiment in which simulating the airflow in the studied room.Three dimensional airflow numerical models are developed to predict air motion within an enclosure. Authorsimulates the three dimensional static airflow and temperature distribution by CFD code FLUENT. Author usedRSM turbulence model to predict air motion. And Author proposed that flow rate of non-symmetrical solutionsis significantly greater than that of symmetrical solutions.S.A. Tassou et al. (2009) [20] performed Insulation efficiency (heat leakage) test by the inner heating method,and Performance tests of the refrigeration system. Author found Losses are structural pockets, air gaps, metalliclatches, structural ribs, hinges, rivets or screws. Author talk about Reefer van Insulated with high quality, lowconductivity material for example polyurethane. Author found that Properties of insulation directly proportionalto age of vehicle and Reduction in CO 2 emissions by hybrid systems. Reduction in the cost of insulation willreduce the refrigeration load. Author also find that COP increases 0.4 to 0.62 after 9 years of operation resulting50 % increase in energy consumption and CO 2 emission. The COP of transport refrigeration systems is quitelow, ranging for around 0.5 at 20 ° C. Author proposed that further research work and development work isneeded to improve efficiency and reduce weight.Li Xiaoyan et al. (2010) [21] study on new cool storage material for refrigerated vehicle in cold chain and workon optimisation of logistic chain and Author proposed that a correct approach to weight losses is a primary goalin cold chain. The insulation material used was polyurethane. Author talk about fresh food supply chain,transportation devices, storage, mainly in order to achieve the purpose of preservation, thus Author talk aboutcold chain logistics. Author find problem that most of the phase change material thermal conductivitycoefficient is small, small cop of compressor, reducing consumption of refrigeration system.Lastly Authorproposed that strengthening mechanism of thermal conductivity also needs depth theoretical analysis.Shouhao Li et al. (2011) [22] did numerical simulation of cooling structure by CFD code FLUENT. Authorassumes the air flow in air duct is three dimensional problems. Using boundary conditions Author done analysison duct and Author conclude that uniformity air flow has great benefit to the temperature of the battery.Table 1 : Comparative Work Done By Various AuthorsAuthor Journal Year Approach FindM.S.SoylemezW. R. daVeigaELSEVIER 1999 EXPERIMENTALOPTIMUMINSULATIONTHICKNESSTurbulenceModelN/ACodeUsedN/AApplicationRefrigeratedTruckELSEVIER 2002 EXPERIMENTAL HEAT TRANSFER N/A N/A Snow bagC.P Tso ELSEVIER 2002 CFD AIRFLOW PATTERN K-ξ FLUENTJ. Moure ELSEVIER 2002D.M.StubbsS.W.TSpenceQingshanShanTeshomeCFD+EXPERIMENTALAIRFLOW PATTERNK-ξ+RSMFLUENTELSEVIER 2004 CFD AIRFLOW PATTERN K-ξ FLUENTELSEVIER 2004 CFD AIRFLOW PATTERN K-ξ FLUENTIEEE 2005 EXPERIMENTAL WTSN NA N/ARefrigeratedcontainerRefrigeratedTruckRefrigeratedcontainerRefrigeratedcontainerRefrigeratedcontainerELSEVIER 2006 CFD AIRFLOW PATTERN K-ξ FLUENT ZonalS. J. James ELSEVIER 2006 CFD Insulation thickness K-ξ FLUENT Refrigerated113

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012and heat transferSilviaTEMPERATUREEstrada ELSEVIER 2006 EXPERIMENTALFROMN/A N/ATHERMOCOUPLESAIRFLOW PATTERNAlainELSEVIER 2006 CFDAND HEAT MASSKondjoyanTRANSFERK-ξ FLUENTPieterVerboven ELSEVIER 2006 CFD AIRFLOW PATTERN K-ξ FLUENTN.J. SmaleDong WangHui JinFranciscoZhijian LiuELSEVIER 2006 CFD AIRFLOW PATTERN K-ξFLUENT+kamelonIEEE 2006 CFD AIRFLOW PATTERN K-ξ FLUENTcontainerRefrigeratedTruckRefrigeratedcontainerRefrigeratedcontainerRefrigeratedTruckRefrigeratedroomASHRAE 2006 CFD AIRFLOW PATTERN K-ξ FLUENT PlenumASHRAE 2006 CFD AIRFLOW PATTERN K-ξ FLUENT PlenumIEEE 2008 CFD AIRFLOW PATTERN RSM PhoneticsFu-YunZhao ELSEVIER 2009 CFD AIRFLOW PATTERN K-ξ FLUENTS.A.Tassou ELSEVIER 2009 EXPERIMENTALLi XiaoyanHongboShouhao LiIEEE 2010 EXPERIMENTALELSEVIER 2011 CFDINSULATIONMATERIAL-PUFFCOOL STORAGEMATERIALPCM FREEZING OFCRYOGENIC GASN/AN/AK-ξN/AN/AFLUENTIEEE 2011 CFD AIRFLOW PATTERN K-ξ FLUENTSlotventilatedenclosureRefrigeratedcontainerRefrigeratedTruckRefrigeratedcontainerRefrigeratedcontainerRefrigeratedcontainer3. CONCLUSIONThe insulation material, airflow pattern and optimum insulation thickness of reefer can be found out bysimulation and experimental results. Maximum journal used fluent code and maximum work done on airflowpattern. Polyurethane is the best insulation material and the optimum insulation thickness was 70mm formaximum efficiency of reefer truck.4. FUTURE WORKTo find pull up time and pull down time readings by experimental work. To find best insulation material fromcomparative study of insulation material by CFD results. To find optimum insulation thickness.5. REFERENCES[1] M.S. Soylemez, Optimum insulation thickness for refrigeration applications (1999) 13-21[2] W. R. da Veiga, Heat transfer coefficient of a snow bag (2002) 1043-1046[3] C.P Tso, Experimental study on the heat and mass transfer characteristics in a refrigerated truck (2002)340-350[4] J. Moureh , Numerical and experimental study of airflow in a typical refrigerated truck configuration loadedwith pallets (2002) 25-42[5] D.M.Stubbs, wrapping strategies for temperature control of chilled foodstuffs during transport (2004) 69-80[6] S.W.T Spence, construction and testing of air-cycle systems for road transport (2004) 503-510[7] Qingshan Shan Wireless temperature sensor network for refrigerated vehicles (2005) 985-994[8] S. J. James, Modeling of food transportation systems a review (2006) 947-955114

Rahul Jain et al / VSRD International Journal of Mechanical, Auto. & Prod. Engg. Vol. 2 (3), 2012[9] Silvia Estrada Thermal performance indicators for refrigerated road vehicles (2006) 889-898[10] Alain Kondjoyan (2006) A review on surface heat and mass transfer coefficients during air chilling andstorage of food products 863-875[11] Pieter Verboven, Modelling transportation phenomena in refrigerated food bulks, packages and stacks:basics and advances (2006) 985-997[12] N.J.Smale, A review of numerical models of airflow in refrigerated food applications (2006) 911-930[13] Dong Wang ,CFD Predictions of Minivan's Front-end Flow Performance (2006) 34-39[14] Francisco, A computational fluid dynamic model of the heat and moisture transfer during beef chilling(2006) 998-1009[15] Hui Jin, Testing and modeling of under floor air supply plenums (2006) 581-591[16] Teshome, A new generation of zonal models (2006) 163-175[17] Zhijian Liu, Correlation between indoor air distribution and pollutants in natural ventilation (2007) 21-26[18] Fu-Yun Zhao, Multiple steady fluids flows in a slot-ventilated enclosure (2008) 1295-1308[19] S.A. Tassou, Food transport refrigeration – Approaches to reduce energy consumption and environmentalimpacts of road transport (2009) 1467-1477[20] Li Xiaoyan, Study of New Cool Storage Materials for Refrigerated Vehicle in Cold Chain (2010) 637-640[21] Shouhao Li, the Natural Ventilation System Study on Electric Vehicle (2011) 5236-5237[22] Hongbo, Simulation research on PCM freezing process to recover and store the cold energy of cryogenicgas (2011) 1-8115