Si mul at i onResul t s

In document 저작자표시 (Page 35-46)

Fig.9showsthesimulationresultsthatwasperformedaspowerofthehalogen lamp modelwaskeptat80% and distancebetween thepipespecimen modeland thehalogen lamp modelwasadjusted to1m,2m and 3m.A shapeofthedefects wassimilartotheactualshapeofthedefects.

According totheFEA simulation results,thetemperatureon surfaceofthepipe specimen modelwasthehighestwhenpowerofthehalogen lampmodelwas80%

and distance between the pipe specimen modeland the halogen lamp modelwas 1m.Moreover,the defects were clearwhile shape ofthe defects was the most similartoactualshapeofthedefects.However,asharpnessofthedefectsvaried according to depth ofthe defects.As distance between the pipe specimen model and the halogen lamp model increased, heat transfer to surface of the pipe specimen modelwasdecreased dramatically.Therefore,theFEA simulation results confirmed the heating effects of the heating device that used halogen lamp.

Consequently,itcould be predicted thatdefects could be welldetected underthe optimal experiment conditions that power of the halogen lamp was 80% and distancebetweenthepipespecimenandthehalogenlampwas2m orless.

Heatingsource

Powerof halogenlamp

model

Heatingtime

Distancebetweenpipe specimenandhalogen

lampmodel

1kW halogenlamp

50%

60sec

1m,2m,and3m respectively

60% 1m,2m,and3m

respectively

80% 1m,2m,and3m

respectively TABLE 4.Conditionsoftheheatingsimulation

(a)distanceofthehalogenlampmodelfrom pipespecimenmodel-1m

(b)distanceofthehalogenlampmodelfrom pipespecimenmodel-2m

(c)distanceofthehalogenlampmodelfrom pipespecimenmodel-3m Fig.7.50% powerof1kW halogenlampmodel

(a)distanceofthehalogenlampmodelfrom pipespecimenmodel-1m

(b)distanceofthehalogenlampmodelfrom pipespecimenmodel-2m

(c)distanceofthehalogenlampmodelfrom pipespecimenmodel-3m Fig.8.60% powerof1kW halogenlampmodel

(a)distanceofthehalogenlampmodelfrom pipespecimenmodel-1m

(b)distanceofthehalogenlampmodelfrom pipespecimenmodel-2m

(c)distanceofthehalogenlampmodelfrom pipespecimenmodel-3m Fig.9.80% powerof1kW halogenlampmodel

2.Cool i ng Si mul at i on Resul t s

A FEA simulation to confirm the cooling effects of the cooling device and investigatetheoptimalexperimentconditionswasperformed aspressuredifference ofthefan modelwasadjusted to 100Pa and 150Pa and distancewasadjusted to 1m,2m and 3m accordingly.In addition,astemperatureofthewaterthatflowed insidethepipespecimenmodelwassetat100℃ and200℃,ananalysiswasmade for60seconds.Table5showstheconditionsoftheFEA simulation.

The simulation resultwere obtained based on the image at30 seconds,which showedthedefectsthemostclearlycomparedtotheresultsofsimulationthatwas conductedfor60seconds.Fig.10showsthesimulationresultsthatwereperformed when thepressuredifferenceofthefan modelwas100Pa,thetemperatureofthe pipe specimen modelwas 100℃ and 200℃,and the distance between the pipe specimen modelandfan modelwasadjusted to1m,2m and3m.Thedeviation of thetemperaturein thedefectpartwasconspicuousunderallsimulation conditions regardlessofthedistancebetweenthepipespecimenmodelandfanmodel.

In addition,Fig.11showsthesimulation resultsthatwereperformed when the pressure difference of the fan modelwas 150Pa,the temperature of the pipe specimen modelwas100℃ and200℃,andthedistancebetween thepipespecimen modeland fan modelwasadjusted to 1m,2m and 3m.Theshapeofthedefects was observed with the naked eye.The defects appeared cleareras the pressure difference in the fan modelincreased regardless of the depth of the defects. Moreover,the defects became more distinctwhen the distance between the pipe specimenmodelandfanmodelwasshorter(1m and2m).

Consequently,the FEA simulation could confirm the cooling effects ofthe fan cooling device.Theoptimalexperimentconditionsincludea pressuredifferenceof 150Pa in the fan and a close distance,such as 1m and 2m between the pipe specimenandfancoolingdevice.

Coolingsource

Pressure differenceof

fanmodel

Temperatureof pipespecimen

model

Distancebetweenpipe specimenandfanmodel

Fan

100Pa

100℃ 1m,2m,3m respectively 200℃ 1m,2m,3m

respectively

150Pa

100℃ 1m,2m,3m respectively 200℃ 1m,2m,3m

respectively TABLE 5.Conditionsofthecoolingsimulation

(a)distanceofthefanmodelfrom pipespecimenmodel-1m (100℃)

(b)distanceofthefanmodelfrom pipespecimenmodel-2m (100℃)

(c)distanceofthefanmodelfrom pipespecimenmodel-3m (100℃) Fig.10.Differentialpressureof100Paonfanmodel

(d)distanceofthefanmodelfrom pipespecimenmodel-1m (200℃)

(e)distanceofthefanmodelfrom pipespecimenmodel-2m (200℃)

(f)distanceofthefanmodelfrom pipespecimenmodel-3m (200℃) Fig.10.Differentialpressureof100Paonfanmodel(continued)

(a)distanceofthefanmodelfrom pipespecimenmodel-1m (100℃)

(b)distanceofthefanmodelfrom pipespecimenmodel-2m (100℃)

(c)distanceofthefanmodelfrom pipespecimenmodel-3m (100℃) Fig.11.Differentialpressureof150Paonfanmodel

(d)distanceofthefanmodelfrom pipespecimenmodel-1m (200℃)

(e)distanceofthefanmodelfrom pipespecimenmodel-2m (200℃)

(f)distanceofthefanmodelfrom pipespecimenmodel-3m (200℃) Fig.11.Differentialpressureof150Paonthefanmodel(continued)

In document 저작자표시 (Page 35-46)

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