Today, as energy resources are depleted and environmental pollution is a problem worldwide, the development of clean energy and more efficient use of the existing energy resources has become very important in the automotive industry. What is the most important to solve this problem is to design and develop engines with high power output and fuel economy and low level of harmful gas emission.

Air movement inside the diesel cylinder has a crucial effect on the formation of mixtures and combustion processes, thus affecting the dynamical character, economy, combustion noise, and emissions of harmful gases of diesel engines, too. Swirl ratio has a great effect on the formation of fuel-air mixtures and combustion process in the cylinder. This encouraged many studies to optimize intake channels.

However, there are some problems in the literature. Generally, the effect of swirl ratio has not been considered in detail because the flow rate is kept constant when considering the effect of swirl ratio on the engine combustion process. In addition, spiral intake channels are introduced for cylinder head intake channels, which is difficult to implement because the demand for intake tube manufacture is too high.

On the basis of a detailed analysis of the effect of intake swirl on the combustion characteristic of a 12hp direct injection diesel engine, Ho Pong Guk, a section head at the Faculty of Mechanical Science and Technology, improved the combustion characteristics of engines by modifying the cylinder head intake channel to provide high swirl ratio with high flow rate.

The proposed method might be useful in practice because it is not difficult to apply and it provides the swirl ratio suitable for combustion.

For further details, you can refer to his paper “Geometry Determination of Cylinder Head Intake Channel Considering the Effect of Swirl Ratio on Combustion Process in a Direct Injection Diesel Engine” in “Proceedings of KUTIC-2025”.

The peel test is widely used for material selection and quality control testing. To learn the properties and adhesion characteristics of material, the test conditions and analytical methods should be used appropriately. The purpose of a peel test is to obtain the main property of the interface, GC, which is usually called fracture energy. The value of fracture energy, GC, should be the main characteristic for the evaluation of bond strength.

There have been many attempts to calculate the fracture energy GC, which reflects bond properties. However, the authors mostly focused on the case of a joint with substrates as adhesives.

Choe Kyong Hyok, a section head at the Faculty of Mechanical Science and Technology, has proposed a method for determining the fracture energy of a polyethylene thermal joint and determined the fracture energy values for several joints.

He performed a finite element analysis to determine the fracture energy values from the peel test data. He used a node release technique to model the crack propagation through the interface of the two membranes. When performing finite element modeling, he accurately reflected the mechanical properties of polyethylene to increase the accuracy of the simulation.

For more information, please refer to his paper “Method for Determining Fracture Toughness of Polymer Adhesive Interfaces Considering Viscoelastic Loss” in “Proceedings of KUTIC-2025”.

Spraying mist has been widely used in environmental purification, nanomaterial manufacturing and chemical industry to promote reactivity and improve cooling properties. Therefore, there have been many studies to improve the spray characteristics. To achieve various scientific and technological purposes such as environmental purification with a small amount of water and reagents, effective nanoparticle preparation using fine mist particles, rapid rise of reaction rate, and fogging with low energy consumption, researchers have investigated nozzle structures and spray methods for generating fine spray particles.

Generally, low pressure spraying is widely used rather than high pressure spraying because the latter has some shortcomings such as high energy consumption, severe wear of equipment, nozzle clogging in operation, etc. However, low pressure atomization is often used in conjunction with low pressure air jet because fine mist particles are difficult to obtain in large quantities.

The combined use of compressed air atomization can contribute to improving the efficiency in various processes including environmental purification, nanomaterial preparation, chemical reaction promotion, etc., due to its low energy consumption and high fogging efficiency.

Paek In Chol, vice dean of the Faculty of Mining Engineering, has investigated the spray characteristics and considered the optimum spraying conditions when low pressure air jet is combined with low-pressure water jet.

Using the Taylor Analogue Breaking (TAB) model, he simulated the droplet breaking up process and studied the time-dependent tearing behavior and the suitable pressure conditions.

The results show that most particles in the central part of the spraying zone are 0.8-12㎛ in diameter, and the spray pressure in the combined compressed air is the most suitable from 0.25 to 0.3MPa when the pressure of compressed air is set to be 0.2MPa.

You can find the details in his paper “Numerical Simulation of Water Spraying Characterization Improvement in Low Pressure” in “Proceedings of KUTIC-2025”.