Suhaimi Illias
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Preferred name
Suhaimi Illias
Official Name
Suhaimi, Illias
Alternative Name
Ilias, Suhaimi
Illias, S.
Bin Illias, Suhaimi
Iliasb, Suhaimi
Main Affiliation
Scopus Author ID
54920300100
Researcher ID
ABB-5405-2020

Research Output

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The role of gas-phase dynamics in interfacial phenomena during few-layer graphene growth through atmospheric pressure chemical vapour deposition

2020-02-14 , Fauzi F.B. , Ismail E. , Syed Abu Bakar S.N. , Ismail A.F. , Mohamed M.A. , Md Din M.F. , Suhaimi Illias , Ani M.H.

The complicated chemical vapour deposition (CVD) is currently the most viable method of producing graphene. Most studies have extensively focused on chemical aspects either through experiments or computational studies. However, gas-phase dynamics in CVD reportedly plays an important role in improving graphene quality. Given that mass transport is the rate-limiting step for graphene deposition in atmospheric-pressure CVD (APCVD), the interfacial phenomena at the gas-solid interface (i.e., the boundary layer) are a crucial controlling factor. Accordingly, only by understanding and controlling the boundary-layer thickness can uniform full-coverage graphene deposition be achieved. In this study, a simplified computational fluid dynamics analysis of APCVD was performed to investigate gas-phase dynamics during deposition. Boundary-layer thickness was also estimated through the development of a customised homogeneous gas model. Interfacial phenomena, particularly the boundary layer and mass transport within it, were studied. The effects of Reynolds number on these factors were explored and compared with experimentally obtained results of the characterised graphene deposit. We then discussed and elucidated the important relation of fluid dynamics to graphene growth through APCVD.

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Effect of Oxygen Gas Exposure on T91 Alloy at High Temperature Oxidation of Steam Reformer

2023-01-01 , Rosdin M.R.H. , Ismail A.A.M. , Hamid A.M.A. , Purwanto H. , Suhaimi Illias , Bakar S.N.S.A. , Ani M.H.

Steam-Methane Reforming (SMR) is one of the most economical ways to produce hydrogen from natural gas. Steam reforming industry is hugely relied on using supercritical power plant where the working temperature of the plant must exceed 600 °C. Along with the high operating temperature, the situation promotes the acceleration of high temperature oxidation. This will cause fouling and spalling of oxide scales at the boiler tube. Eventually, fouling will reduce heat transfer between the tube and steam generated, causing a higher temperature is needed to produce steam. Until now, the only approach used by the industry is to manually replace the corroded boiler tube. Other than that, many studies have been conducted on the behavior of boiler tubes at temperatures exceeding 800 °C. However, to our knowledge, no study has been done to investigate the air electrolyte substrate interfacial electrochemical reaction at high temperature. This project was carried out to investigate the corrosion potential of T91 boiler tube at 650 °C for 2 h, 8 h, and 12 h, measure the current density (Icorr) by calculating corrosion potential (Ecorr) value using Tafel Extrapolation and determine the oxidation potential of oxygen gas at 650 °. The oxide layer thickness at exposed temperature was determined to measure the oxidation kinetics. The study concludes that there was an increase of 8.49% in current conductivity between the blank experiment and T91 alloy oxidation potential test. The oxidation process was following the parabolic rate law which manifest that the corrosion is controlled by ionic diffusivity in the oxide layer. The oxide layer formed on the sample has an average thickness of 54.10 μm and this value can be used to calculate the oxidation kinetics of the sample using parabolic rate constant, Kp, resulting with the value of 6.78 × 10−14 m2/s.

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Maximum spreading diameter of a water droplet after impact on a hot surface beyond Leidenfrost temperature

2023 , Mohd Zaidul Fikry Juhar , Muhammad Sofwan Mohamad , Suhaimi Illias , Nasrul Amri Mohd Amin , Suhaila Hussain , Mohd Hanafi Ani

The impact of liquid droplets on heated surfaces are relevance across a range of applications. The maximum spreading diameter of water droplet during impact on hot surface was experimentally studied. The surface was made of aluminium. The diameter and height of the aluminium block was 70.0 mm and 30.0 mm, respectively. During experiment, the test surface was heated beyond Leidenfrost temperature. A high-speed video camera was used to capture the droplet images from the first impact until the droplet reached maximum spreading condition. The frame rate was set to be 2,000 fps. Distilled water was used as the test liquid. The impact height was set to be about 65.0 mm. From the high-speed images analysis, the droplet diameter was found to be approximately 4.5 mm. The measured droplet maximum spreading diameters were found to have a good agreement with theoretical calculation.

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High Temperature Oxidation of T91 Alloy of Steam Reformer

2023-01-01 , Rosdin M.R.H. , Ismail A.A.M. , Hamid A.M.A. , Purwanto H. , Suhaimi Illias , Bakar S.N.S.A. , Ani M.H.

Steam plays a significant role in the reforming process of hydrogen. It is generated in a waste heat recovery unit at temperature of 650 ℃. Along with the high operating temperature, the situation promotes acceleration of high temperature oxidation. This will cause fouling and spalling of oxide scales at the boiler tube. Eventually, fouling will reduce heat transfer between the tube and steam generated, causing a higher temperature is needed to produce steam. Until now, the only approach used by the industry is to manually replace the corroded boiler tube. Other than that, many studies have been conducted on the behavior of boiler tubes at temperatures exceeding 800 °C. However, to our knowledge, no “in-situ” study has been done to investigate the high temperature electrochemistry aspect of boiler tubes. A review conducted by B.A Pint [1] in his paper mentioned that it is notoriously difficult to imitate the harsh environments in laboratory scale. Popov [2] stated that the only available method to decrease corrosion rate at high temperature corrosion and hot corrosion is only by implementing protective coatings. This project was carried out to investigate the corrosion potential of T91 boiler tube at 650 °C for 30 min, 1 h, 2 h, 8 h, and 12 h, measure the current density (Icorr) by calculating corrosion potential (Ecorr) value using Tafel Extrapolation and determine the current conductivity of oxygen gas at 650 ℃. Apart from that, the oxide layer thickness at exposed temperature is also determined to measure the oxidation kinetics. The study concludes that there was an increase of 8.49% in current conductivity between the blank experiment and T91 alloy conductivity test. The oxide layer formed on the sample is significant to calculate the oxidation kinetics of the sample using parabolic rate constant (Kp), resulting with the value of 6.78 × 10–14 m2s−1.

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Prediction of maximum spreading time of water droplet during impact onto hot surface beyond the Leidenfrost temperature

2021-12-01 , Suhaimi Illias , Suhaila Hussain , Rahim Y.A. , Muhammad Asri Idris , Mohamad Ezral Baharudin , Ismail K.A. , Ani M.H.

When a water droplet impacts on a heated surface in the film boiling regime, it will spread, recede, and finally bounce off from the heated surface. These unique liquid-solid interactions only occur at high surface temperatures. Our main objective in this research is to measure the maximum spreading and residence time of the droplet and the findings were compared to theory. We focused our study in the film boiling regime. Brass material was selected as the test surface and was polished until it became a mirror polished surface. The temperature range for this experimental work was between 100 °C up to 420 °C. Degassed and distilled water was used as the test liquid. The high speed video camera recorded the images at the rate of 10,000 frames per second (fps). As a result, it was found that the experimental value of maximum spreading and residence time agreed closely with the theoretical calculation. A new empirical formula that can be used to predict the maximum spreading time in the film boiling regime is also proposed.

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Metal Dusting Led Failure in a High-Temperature Condenser

2023-01-01 , Kaderi A. , Bakar S.N.S.A. , Ani M.H. , Suhaimi Illias , Osman M.S.

Corrosion is a metallurgical problem that occurs frequently in a power plant, plant inevitable, especially in the present days, since higher efficiency of a power plant is required and thus the process temperature is increasing. Choosing the right materials for pipeline is very crucial since it is affecting the service life and operational reliability. The research is done to study the oxidation behaviour of ferritic alloy for power plant. A failed component from a gas combined cyclic thermal power plant was received and a failure analysis is done to investigate the cause of failure of the equipment. Results from the analysis suggested that the pipe was exposed to high temperature oxidation and metal dusting. Metal dusting mechanism and how it affects materials in high temperature condition is then identified and explained in this work.

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Critical heat flux and Leidenfrost temperature on Electrical Discharge Machining (EDM) - constructed hemispherical surface

2021 , Suhaimi Illias , Suhaila Hussain , Rosman N.A. , Mohamad Ezral Baharudin , Mohamad Shaiful Ashrul Ishak , Khirul Azwan Ismail , Mohd Hanafi Ani

This paper reports a Leidenfrost temperature on hemispherical surface constructed by Electrical discharge machining or known as EDM. We focus our study on the droplet evaporation lifetime to investigate and identify the Leidenfrost temperature. Three (3) different types of materials were selected i. e such as Brass (Br), Aluminum (Al) and Copper (Cu). Meanwhile, ethanol liquid has been chosen as the test liquid. Ethanol liquid was elected due to its low boiling point of approximately 78 °C. The droplet impact velocity and droplet diameter was approximately 1.129 m/s and 3.476 mm, respectively. As a result, we finally succeeded in determining the Leidenfrost temperature for all materials mentioned above. On top of that, all the Leidenfrost temperature results, TL were close to the superheat limit temperature of ethanol liquid, TSL which is about 197.8 °C.

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