Research Unit for Studying the Evaporation Rate of Flammable and Combustible Liquids under Variable Ventilation

The Research Unit for studying the evaporation rate of Flammable Liquids (FL) and Combustible Liquids (CL) based on ventilation parameters (The Unit) is a specialized hardware-software complex. It is designed to investigate how the evaporation of FL and CL depends on various ventilation parameters. The ultimate goal of this research is to determine the optimal ventilation modes required to prevent the formation of fire and explosion hazardous concentrations inside industrial process equipment while it is being decommissioned for routine maintenance and repair operations.

Using the Unit, it is possible to:

1. Determine the correlation between the evaporation rate of FL/CL inside process equipment and the velocity and temperature of forced ventilation;
2. Measure the concentration of FL and CL vapors within the volume of the process equipment;
3. Set and test various combinations of forced ventilation parameters (airflow velocity and air temperature);
4. Select the specific type of FL or CL before initiating the experiment to ensure accurate calculation of vapor concentration in the air;
5. Acquire empirical data and output it to a local display and a PC for further processing to build mathematical models and identify optimal ventilation parameters.

The required volume of the target FL or CL is poured into the test chamber. Using the control module, the operator selects the specific liquid being tested and sets the desired airflow velocity and target temperature. Upon pressing the “Start” button, the forced ventilation begins, maintaining the set velocity while ramping up to the target temperature. To maintain the exact airflow velocity and temperature, the system uses a ventilation module consisting of a fan, a heating element, and a temperature sensor. The fan power is controlled via Pulse Width Modulation (PWM). To achieve the precise target temperature across the entire range of possible airflow velocities, the heating element is also controlled via PWM, with the duty cycle dynamically calculated by an onboard PID controller. The measurement module records the FL/CL vapor concentration at the outlet of the ventilated chamber as well as the exhaust temperature. It manages the ventilation module, provides the user interface for inputting settings, and controls the entire measurement process. The acquired data is displayed on the local screen and transmitted to a PC.

The Unit’s microcontroller is equipped with a bootloader, allowing the firmware to be easily updated to expand its functionality in the future.

Practical Application and Awards:

• The Unit is actively used in the academic curriculum for laboratory training and scientific research purposes.
• The system was awarded the “3rd Degree Diploma for the Author Collective of a Scientific Exhibition Exhibit” for the project: “Hardware-software complex for studying the evaporation rate of FL and CL depending on ventilation parameters to prevent hazardous concentrations in process equipment during maintenance,” at the “Best Scientific Exhibition Exhibit” competition at the National University of Civil Defence of Ukraine (NUCZU) on May 20, 2016.

 

The Unit was developed for, and with the active participation of, the Department of Fire Prevention in Populated Areas at the National University of Civil Defence of Ukraine.