Reduction of energy loss in Al alloys transport

Technological forum 2016

Department of Manufacturing Technology, Faculty of Mechanical Engineering,

Czech Technical University in Prague

Technická 4, 166 07 Praha 6

Reduction of energy loss in Al alloys transport

Aleš Herman, František Štourač, Irena Kubelková, Martin Kubelka 1) Jaroslav Doležal 2)

1) Department of Manufacturing Technology, Faculty of Mechanical Engineering, Czech Technical University in

Prague, Technická 4, 166 07 Praha 6,

[email protected]

2) METAL TRADE COMAX, a.s., Velvary

Abstract in English language: The paper deals with the melt Al alloy transportation of rotary oxy-

combustion melting furnace in holding furnaces via transport trays. Practically work examined a draft

slope gutter and verification functions trough. The paper describes the energy loss during the passing

of the metal to holding furnaces. The work also set the imager to work with liquid aluminium alloy.

Keywords in English language: metal transport, transport trough, measurements of temperature fields, infrared camera, thermo graphic video

1. Introduction

The re-melting of aluminum scrap is made in new melting line. The melting line is assembled from:

• gas rotary furnace for content up to 16 tons,

• trays for melt transport,

• holding furnaces.

The line is new and there is needed solving the problem of melt heat lost during transport to holding furnaces. The paper deals with the problematic of measurement of heat lost. The main goal of this paper is decreasing of heat lost transport melt metal and found optimal combination of trays material and insulating coating.

The possible hypothesis:

1. covering of trays

2. accelerating of melt flow

3. decreasing of melt friction in trays (coating, change of trays lining, pre-heating of

channel)

For the research of heat lost quantity was used next equipment:

• Infrared camera FLIR T640 with SW TOOLS+,

• Contact thermometer Ahlborn Therm 2420 with thermocouple FT 106 (fig. 1),

• stopwatch,

• immersion thermometer Diterm 97.





2. The process simulation

The tray and pouring to tray was simulated in foundry simulation software NovaFlow&Solid. There

was simulated flowing of melt metal in tray. The position on thermocouple in simulation see fig. 2

and obtained thermal field during filling is on fig. 3

Figure 1 – Temperature measuring by contact thermometer in tray

Figure 2 – Set up of thermocouple in simulation

Figure 3 – Temperature field in trays during melt flowing in tray





The distribution of temperature in thermocouple demonstrated fig. 4

Figure 4 – Course of temperature in thermocouples from simulation

3. Real experiment

The process of flowing of melt was analyzed in special software for infrared camera, where is

possible to analyze thermo-graphical video. On Fig. 5 is demonstrated the thermal field during

flowing of melt metal.

From this video was analyzed the course of temperature in elementary tray section (Li1 – 10 see Fig.

2). The course of thermal field is strongly dependent on emissivity. Emissivity of melt aluminum alloy

is difficulty ascertainable. The table of emissivity describe only heavily oxidized surface of aluminum

alloy by temperature 599°C (the value of emissivity is 0, 19). There is problem that the emissivity

depends on several factors:

• Temperature

• Distance from the object

• Surrounding temperature and moisture

• Reflected temperature

• Surface

• Humidity

The distribution on temperature field during flowing in trays is demonstrated on Fig. 6

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Figure 5 – Temperature measuring by contact thermometer in tray

Figure 6 – Thermographic record of temperature course from section above





The main problem is right set up of emissivity. Emissivity was calibrated by immersion thermometer

on value 0, 21 by reflected temperature 40°C, distance from camera was 14 meters and humidity was

61%.

Figure 7 – Measurement by immersion thermometer in melt

4. Describing of course records

Firstly was started pouring – the velocity of pouring was app. 0, 3 m.s-1 (really melt flow 10 m per 30

s). From figure 6 is possible see arisen temperature to app 900°C, after 5 minutes is pouring to tray

stopped and melt metal in furnace is mixed up by rotation. In furnace is hot ash and slag and

temperature of melt is increasing. There is possible see decreasing of temperature and cooling on

tray. After mix up operation continue pouring rest melt aluminum alloy – increasing of temperature

up to 1200°C and pouring of rest metal.

The main problem is the changing emissivity – this is made the non-discrete variable and is need to

use high mathematical software for analysis of melt metal.

After analyzing of results In MatLab where we phased after elementary steps described above is

possible obtain linear relation of course of temperature on tray see fig. 8





Figure 8 – The course of smoothing curves Li1 and Li10 in MatLab

5. Conclusion

There was described problem of thermal lost. In the next phases is need made more analyzes for

definitive results.

Partly conclusions from first several analyzes is demonstrated that for decreasing of heat in tray is

possible to use insulated covering after finishing pouring and using of good insulation coating in tray

with lower friction properties – for quickly transport on the tray.

6. Anknowledgment

The research was financed by by SGS16/217/OHK2/3T/12 Udržitelný výzkum a vývoj v oboru strojírenských technologií and with Inovation voucher of Central Bohemian Region.

Bibliography

[1] HERMAN, Aleš; ČESAL, Marek. Temperature stability of the process of production of wax

patterns for investment casting technology model.MANUFACTURING TECH, 2012.

[2] BERNARD, Vladan, et al. Infrared camera assessment of skin surface temperature–Effect of

emissivity. Physica Medica, 2013, 29.6: 583-591.

[3] ZHANG, R.-H., et al. Study of emissivity scaling and relativity of homogeneity of surface

temperature. International Journal of Remote Sensing, 2004, 25.1: 245-259.

[4] IMRIE, David A. CALIBRATING THE THERMAL CAMERA-As thermal cameras gain ground in

the commercial market, testing becomes critical.Photonics Spectra, 2009, 22.12: 49.

[5] SKOUROLIAKOU, A. S., et al. Infrared Thermography Imaging: Evaluating surface emissivity and

skin thermal response to IR heating. e-Journal of Science & Technology (e-JST), 2014.

[6] RAMEGOWDA, Dinesh, et al. Thermal camera calibration. U.S. Patent Application No 12/883,568,

2010.

Reviewer: Fill the reviewer name (and the department) of your post title.

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Documents

Reduction of energy loss in Al alloys transport