Laboratory Equipment

The test equipment used in the Heat Transfer and Fluid Flow Laboratory was developed here under long term experiences with industry cooling considering way of calculation, modeling and simulation. The equipment was designed to work with plenty of modifications that usually occur in industrial spray cooling applications; however the lab is flexible and able to develop and built equipment for measuring under very specific requirements. 

Introduction

When working in the lab, we learnt that the sophisticated measurement technology is essential for getting good results. Therefore we are continuously observing influences on the result data, following news in instrument technology, learning and improving. Heat Transfer and Fluid Flow Laboratory also participate in plenty of related projects e.g. development of new thermal and pressure sensors for rolling.


High Temperature Test Bench

The high temperature test bench is used to simulate spray cooling at high initial temperatures. The typical application is continuous casting where the experiment usually starts at 1200°C and finishes below 500°C. The main part of the stand is a test plate, made of an austenitic steel, sized 600x320x30 mm. The test plate embedded by a set of thermocouples is during experiment stable while the nozzles spraying upward move under the plate. The spray height and nozzle velocity are variables.

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       Scheme of the high temperature test bench
3D model of the high temperature test bench during experiment


Experimental procedure:

  • An electric furnace heats the test plate to an initial temperature of the experiment (1200°C).
  • The water/air pressures in the nozzles covered by deflector are adjusted.
  • When the furnace is put aside, the deflector is opened and the spraying nozzles start to move under the test plate according to requirements.
  • The temperatures are recorded by thermocouples and saved to data logger located outside the spray box in a control room.
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The left picture shows the high temperature test bench when the test plate with embedded thermocouples is heated (from its bottom side) to an initial experimental temperature by electric heater, on the right side the electric heater is put away and  the test plate is sprayed by set of nozzles

Linear High Speed Test Bench

This experimental stand was built to study the cooling of linearly fast moving objects. The cooling of long rolled products (beams of various profiles) or the cooling of flat rolled products are typical industrial applications. Given that the movement of the stand is possible to stop at required positions for required duration, it is also oftentimes used for various other projects.
 
The stand allows speed of a tested sample up to 10 m/s, however the typical speed of 5 m/s is applied. The conception of a long girder with a draw trolley which can rotate around its longitudinal axis enables more sample positions respect to the gravity.

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Scheme of linear test bench, 1 – headers with nozzles, 2 – pressure gauge, 3 – test plate, 4 – motor moving trolley, 5 – girder carrying trolley, 6 – movable trolley, 7 – data logger, 8 – heater, 9 – water tank, 10 – pump, 11 – control valve

The girder is divided into three two-meter-long sections. The sections are used for the trolley's acceleration or deceleration. The velocity of the trolley is constant in the mid section and it is here where the sample embedded by the thermocouples is quenched by the spray nozzles. The nozzle types, their arrangement and the feeding pressure together with the sample velocity are changeable parameters usually intended to be designed.
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The 3D model of the linear test bench; the electric furnace is schematically drawn by red colour and the test plate cooled by two nozzles is drawn yellow colour  

Experimental procedure:

  • A steel sample is heated to an initial start temperature in an electric furnace.
  • The heated sample placed on the trolley is set up into the spraying position.
  • The pump for the water gets going and the trolley controlled by computer runs several times through the cooling section under given conditions.
  • The temperatures recorded by thermocouples in the steel sample are saved to data logger together with the trolley position.

Vertical High Speed Test Bench

This apparatus serves for measurement of cooling intensity vertically moving samples. The maximum weight of sample is 25 kg and can be moved by velocity up to 5 m/s which is constant for at least 1 m of its movement. The vertical bench is also equipped by furnace for heating of samples.

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Scheme of vertical test bench, 1 – collector with nozzles, 2 – pressure gauge, 3 – test plate, 4 – motor with rope, 5 – girder carrying trolley, 6 – movable trolley with position sensor and datalogger for recording temperatures and position of the test plate, 7 – heater, 8 – water tank, 9 – pump, 10 – control valve

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The vertical test bench with the test sample in the electric furnace in the left picture; the vertical test bench where the furnace is put away and the sample runs  into the cooling section in the right picture

Experimental procedure:

  • A steel sample is heated to an initial start temperature in an electric furnace.
  • The water pump is switched on and the water pressure is set up.
  • The furnace is put away from the sample placed at the trolley.
  • The trolley runs several times through the cooling section under given condition.
  • Temperatures recorded by thermocouples in the steel sample are saved to data logger together with the trolley position.
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A test plate running in the cooling section of the vertical test bench   

Rotating Test Bench

The rotating test bench is designed for investigation of cooling effects on the rotating cylindrical surfaces. The parameters of the bench are adapted to the main application which is design of cooling systems of rolling-mill working rolls. The main part of the equipment is roll with diameter of Ø 650 mm and width of 600 mm powered by motor for pump station of 150 kW that allows rotational speed 0-5 rps. The roll is equipped by thermocouples measuring temperature while the roll surface is cooled by spraying nozzles.

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Scheme of rotating test bench, 1 – roll, 2 – pressure gauge, 3 – water supply, 4 – manifold, 5 – nozzle, 6 – test segment, 7 – electric motor, 8 – datalogger

There is a test segment located on the roll surface. This part of the perimeter is sophistically embedded by thermal sensors that are during spraying connected with datalogger. Only the neighbourhood of the test segment is heated to required initial temperature before the cooling experiment.

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3D model of rotating test bench that is before experiment covered by deflector, the electric furnace prepared to reheat the test segment of the roll is placed in the back side of test bench in the left picture; on the right deflector is opened and nozzlles spray the roll surface         
            
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The thermal sensors with thermocouple wire installed into the roll

Experimental procedure:

  • An external electric heater heats the test segment of roll equipped by thermal sensors.
  • When uniform starting temperature is reached, the heater is removed from the roll; the roll is covered by deflector.
  • The rotation of roll, still covered by deflector, and the pump station are switched on and the coolant pressure is set up.
  • When all experimental conditions are set up, the deflector is opened and the cooling starts.
  • The temperatures are recorded by thermal sensors during cooling and saved to data logger.
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The rotating test bench with closed deflector shortly before experiment when the datalogger has to be switched on in the left picture; in the right picture there is rotating test bench during cooling experiment
             
Besides the rotating test bench with diameter of Ø 650 mm, another one with diameter of Ø 350 mm is available. The roll is placed in closed box with coolant loop that enables to test cooling characteristics of special chemicals. 

Test chamber for performance measuring of heating and cooling elements

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The basis of the test chamber device with the dimensions 4x4x3 m and was made strictly in accordance with the Czech technical standard DIN EN 442-2 "Radiators: tests and evaluation", which is the Czech version of the European Standard EN 442-2:1996. The whole device is designed to fully suit cited standard and thus allow measurement of heat output heaters in accordance with applicable legislation.

The operation of the test facility is secured by a complex system of heat pump, reservoirs of heat and cold, electric boilers, air handling and distribution systems in walls, floors and ceiling of the chamber. With the help of these components and a special computer program it is possible, basically in automatic mode, to measure and evaluate the performance of the heating or cooling element placed in the test chamber circle.www.heatlab.cz

Detailed information (Read more): Test chamber (PDF) Test chamber (PDF) (639.62 KB)


Other Equipment

  

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Two types of infrared line scanners Raytek are available; RAYTMP150MT for measuring in temperature range of 100 – 800°C and RAYTMP1501M for measuring in temperature range of 600 – 1200°C



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Equipment for impact pressure measurement



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Equipment for thermocouples calibration

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Metallographic laboratory and microscopy

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Chemical and mechanical analysis

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Other equipment as separate electric furnace, pumps, spray cooling unit with closed coolant loop for small stationary samples

Additional Information

can be found in Publications of the Heat Transfer and Fluid Flow Laboratory.