turbulators, pin fin tubes, fin tubes, turbulator

The people behind research and development.

Our Research and Development team is vastly multidisciplinary and combines expertise in electronics, smart motors & controllers, machine programming, systems control and data acquisition, heat transfer, statistics, and mechanical engineering.

The ability to stay with a problem till its most logical solution is arrived at is what’s vital in research projects. Something this team has in spades and it’s allowed the individuals within it to take on several roles.

Customized Product Machinery Development.

Given that we make unique, proprietary products, the machinery to make them also needs to be made in-house.

Efficiency calls for the machines to be made programmable with precision controls and movements. This allows us to tweak the product characteristics. For example, we can, through programming a suitable recipe in our machines, make a turbulator where its geometry varies along the length of the tube to match the changes in a liquid’s viscosity profile along its length.

To do this we have to lean heavily on electronics, smart motors, sensors, and software.

Product testing, during and after development.

A product prototype needs to be tested and tweaked several times before it is optimized and made just right for the application. So, we need efficient Test Rigs which can give a complete performance curve of the product in hours so that it can be tweaked further till optimization is complete.

Which is why we designed and set up a completely automated SCADA controlled rig that can capture and record thousands of data points in a matter of hours.

Analysis of data generated.

This requires a combination of heat transfer knowledge, statistical techniques and pure math. The data generated has to then be made ready for input into major heat transfer software.

Development of applications.

Our team constantly adapts our technology to new applications. It also actively seeks new applications that would fit our available technology. This keeps our R & D team busy and happy.

Turbulator Testing Rig.

The rig for testing turbulators consists of:

  1. A cloud connected computer on which sits a Schneider SCADA (System Control and Data Acquisition) system.
  2. A control panel with a PLC (Programmable Logic Controller). This PLC, on instructions from the SCADA, controls in real-time all the actuators and sensors in the rig. This gives the SCADA program complete control and allows the establishment of long recipes of actions to be taken and data to be acquired.
  3. SCADA controlled 150 kg per hour boiler.
  4. SCADA Temp Controlled 300 litre hot oil tank.
  5. SCADA Flow Controlled 125 litre per minute gear pump for oil.
  6. Oil Flowmeter (Feeding back real-time flowrate data to SCADA)
  7. Differential pressure gauge for oil (Feeding back real-time pressure changes across the inlet and outlet of the tubeside of the heat exchanger).
  8. Temperature sensors at the inlet and outlet of the heat exchanger on the tubeside (feeding back real-time data to SCADA).
  9. 3 meter long interchangeable heat exchanger. The exchangers have oil in the tube side and water on the shell side.
  10. 2000 litre water tank (with temperature sensor feedback to SCADA)
  11. SCADA Controlled 500 litre per minute water pump.
  12. Water Flow meter (with feedback to SCADA).
  13. Temperature sensors at shell-side inlet and outlet (with feedback to SCADA).
  14. Oil in the tank currently is MAK 220 oil. We have tested the viscosity of this oil at 5-degree intervals from 40 to 120 and entered into the SQL database created for SCADA.

Testing Procedure.

Input Parameters

  1. A 3-meter turbulator is inserted into the exchanger. All turbulator and heat exchanger construction details are entered into SCADA.
  2. The SCADA recipe is set where:
    1. The temperatures at which to test the oil are entered. Usually 6 temperatures at 10 degree intervals are set.
    2. Then the flowrates to test at are set. Usually this is set at 10, 20, 30, 40, 50, 60, 70, 80 and 90 LPM.
    3. The test interval is set. This determines the interval at which all data is to be recorded. This is generally set at 5 to 10 seconds.
    4. Then the number of readings to be taken at each flowrate for a given temperature run is set. We usually set this at 60 which is double the statistical number required for a sample set.
    5. The maximum allowable pressure drop is set. We usually set this to 5 bar.
  3. Hit the start button and the SCADA takes over.

Once the program sequence begins, SCADA does the following:

  1. Heats the oil to the first set temperature.
  2. Once this temperature is reached, it starts the pump and stabilizes the flow to the first set level.
  3. Once the flow has stabilized, the system takes the set number of readings specified at the time interval specified.
  4. Once the readings have been recorded, the flow rate is increased to the next level and after stabilization the readings are taken again. This procedure is repeated till all the flow rates are completed or the process is stopped because the pressure drop limit has been reached.
  5. Once the complete run for a given temperature has been reached the oil is heated to the next temperature and the entire flow-temp cycle is repeated. This process continues till the final temperature and flow rate have been reached.
  6. Once the testing has been completed, SCADA switches off the boiler and the system is moved to cool down mode where the oil is pumped through a multi-tube exchanger to cool it down rapidly for the next test cycle.
  7. The data collected is moved to the TRD (Thermodynamics Research Division) cloud.
  8. It is then scheduled for analysis.

Data Analysis.

  1. Using the collected data, the Reynolds number, Prandtl number, jH Factor and f factor are calculated for every data point.
  2. This data is then plotted as a Graph and the power curves derived for:
    1. jH Factor
    2. f Factor
  3. For each power curve the R^2 value is noted.
  4. The data is now ready to be inputted into the appropriate software or used for other calculations.

The entire procedure is outlined in the following animation:

Wind Tunnel Setup.

The wind tunnel to test our wire wound fin tubes consists of the following:

  1. A cloud connected computer on which sits a Schneider SCADA (System Control and Data Acquisition) system.
  2. A control panel with a PLC (Programmable Logic Controller). This PLC, on instructions from the SCADA, controls in real time all the actuators and sensors in the rig. This gives the SCADA program complete control and allows the establishment of long recipes of actions to be taken and data to be acquired.
  3. SCADA controlled 150 kg per hour boiler.
  4. Wind Tunnel is induced draft, 21 feet long with a test section which can hold an air-cooled heat exchanger of 300mm width, 300 mm depth and 1000 mm length.
  5. The fan is induced draft and with a variable speed drive controlled by SCADA. It generates a pressure of 8 inches water column.
  6. There is a Pitot Tube with a differential pressure gauge (DPG) having feedback to SCADA that records the air velocity.
  7. There is a DPG with feedback to SCADA which measures the airside pressure drop across the two sides of the test exchanger.
  8. There are several temperature sensors with feedback to SCADA on both sides of the test exchanger placed at several points to record the temperature.
  9. On the Steam side (inside the tubes) there is a steam trap (to ensure dry steam) and temperature sensors.

Testing Procedure.

Input Parameters

  1. The test exchanger is fitted in the wind tunnel and the steam connection is secured. The heat exchanger construction details are entered into SCADA.
  2. The SCADA recipe is set where:
    1. The different air flow rates at which the exchanger is to be tested is entered into the recipe. Usually this is set at 200 feet per minute, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400 & 1500.
    2. The test interval is set. This determines the interval at which all data is to be recorded. This is generally set at 5 to 10 seconds.
    3. Then the number of readings to be taken at each flowrate is set. We usually set this at 60 which is double the statistical number required for a sample set.
  3. Hit the start button and the SCADA takes over.

Once the program sequence begins, SCADA does the following:

  1. Fires up the boiler and raises it to the preset pressure/temperature.
  2. Once this temperature/pressure is reached, it starts the fan and stabilizes the flow to the first set level.
  3. Once the flow has stabilized, the system takes the set number of readings specified at the time interval specified.
  4. Once the readings have been recorded the flow rate is increased to the next level, and after stabilization the readings are taken again. This procedure is repeated till all the flow rates are completed.
  5. Once the testing has been completed, SCADA switches off the boiler.
  6. The data collected is moved to the TRD (Thermodynamics Research Division) cloud.
  7. It is then scheduled for analysis.

Data Analysis.

  1. Using the collected data, the Reynolds number, Prandtl number, jH Factor and f factor are calculated for every data point.
  2. This data is then plotted as a Graph and the power curves derived for:
    1. jH Factor
    2. f Factor
  3. For each power curve the R^2 value is noted.
  4. The data is now ready to be inputted into the appropriate software or used for other calculations.

The entire procedure is outlined in the following animation:

Data Access and Availability.

To simplify our customers’ interaction with this massive databank we’ve dichotomized customers into three types based on the platform they have.

Customer types:

  1. Customers who have HTRI.
  2. Customers who have HTFS/Aspen/Hysys.
  3. Customers who use their own proprietary calculations.

100% Compatibility in major heat transfer softwares.

Before we get into the mechanics of how one can use our data in major heat transfer software, we must highlight the fact that we enlisted the services of an independent HTRI Member consultant to harmonize our f and j inputs into major heat transfer software. The result is 100% compatibility.

What was done:

  1. The equation forms for f and j in major heat transfer software are slightly different.
  2. While we aren’t at liberty to disclose them here, let’s just say that it involves a conversion from a Nusselt J factor to a Colburn J factor.
  3. Furthermore, the f factor that we used needed to first be made dimensionless and then put in the appropriate equation form.
  4. Post harmonization, 20 readings from our test rig were taken for verification of these harmonized f and j inputs and the results showed 100% compatibility.

Data Sharing Protocol for HTRI Members.

Customers with HTRI simply need to send us their design file (.htri extension) and we can input the factors for the insert that’ll fit that application from our ever-growing databank.

Steps:

  1. The customer sends us the design.
  2. We use our proprietary turbulator pre-selector to see which turbulator optimally matches both the hi and pd goal of the design.
  3. We then input the f and j values of that turbulator into the fj curves section of our HTRI Xace software and send the completed data sheet back to the customer.
  4. The HTRI fj curves section works in one of two ways.
    1. A three-point Reynolds v j and f interpolation.
    2. A power curve where a*Nre^b is inputted.
  5. When the data sheet comes to us we know the entry, midpoint and exit Reynolds numbers give the most accurate results and so will input those into the fj curves section.

This entire process if timed takes less than 5 minutes

Data Sharing Protocol for ASPEN Users.

We’re currently in talks with a partner of ours in Malaysia (who is an HTFS member) to do the f and j input harmonization for HTFS. It should be done shortly. That being said, we offer viable options to HTFS members too.

Clients using HTFS can:

  1. Send us their HTFS Aspen or Hysys design.
  2. We’ll replicate that design in HTRI.
  3. We will then input the f and j factors in the fj curves section to get the final output.
  4. We will send back the final output as an HTRI data sheet.

DSP for non HTRI/HTFS ASPEN Members.

There are many clients who lean on their own proprietary calculations to design their exchangers. We can really help in this regard as we have our data available in multiple equation forms.

The workflow would be as follows:

  1. Send us your application specifics. (target hi, fluid properties, pressure drop allowable, dimensions of exchanger, number of passes etc.)
  2. We’ll select a turbulator using our proprietary selection tool and give you the f and j values to input into your equation forms.
  3. We can even do the calculations for you if necessary.
  4. This makes it very easy to recommend a turbulator that can not only match the performance needed but be safe in terms of pressure drop expectation.

Full Data Integration for Special Cases where NDAs are in place.

We take our data security very seriously but put a vote of confidence in our most prized clients.

On the signing of an exhaustive Non Disclosure Agreement we would be willing to share the following data with you:

  1. The proprietary turbulator pre-selector to match a turbulator to a given hi and pd expectation.
  2. The power curves for every insert we have on file. Which is close to 100 models and counting.
  3. This will allow you to vary your designs up or down in terms of flowrates, inlet temps and sizes and still get the result without having to input multiple f and j values for different Reynolds Numbers.

This is a process that would take no more than 5 minutes of design time.