In this paper, we determine the bubble size and velocity from air bubble generation (MBG) in a diesel using optical methods. A KTM Series Pump was used to generate micro air bubbles in diesel. The air bubble radius and velocity measurements can be useful parameters to optimize the bubble generation process. Two optical systems were used for measurement air bubble sizes and their velocities in diesel. First, the optical system without an objective lens was used to determine the velocity of air bubbles in diesel. Another optical system with a 10× objective lens was used to obtain the size distribution of air bubbles generated in diesel. An available optical system with a 10× objective lens can detect a bubble diameter greater than 3.3 µm that air bubble images were processed using the ImageJ program. We measured the size distribution of air bubbles generated using the ImageJ program. The micro air bubble radius measured in diesel was found to be 6.26 µm in the sample after a month from air bubble generation. In addition, the particle image velocimetry (PIV) technique was used to measure the velocity field. Then, we used the OpenPIV program for PIV image processing. The highest velocity distribution was determined to be 90 mm/s for diesel without air bubbles and 20 mm/s for diesel with air bubbles after a month of the bubble generation.

The equivalence ratio ranges were found between 22.77 and 42.93 for the Saudi LPG/air mixture using a traditional Bunsen burner. An operation problem was found with a traditional Bunsen burner for the Saudi LPG/air mixture, especially in a lean mixture. Therefore, a Bunsen burner was successfully modified to overcome the limits of operation with different mixtures of Saudi LPG/air and a stable flame was obtained. The equivalence ratio ranges were found between 0.68 and 1.30 using the modified Bunsen burner. A premixed flame was used for the modified Bunsen burner. A MATLAB algorithm was successfully applied to flame image processing and measurement of laminar burning velocity. The laminar burning velocity was determined to be approximately 35±0.91cm/s under stoichiometric conditions using the modified Bunsen burner for the Saudi LPG/air mixture. The half-cone angle of the flame was found to be 16.20±0.76°. The minimum flame height was observed to be 21.50±0.22mm above the Bunsen burner exit.

A pyrometer system is an optically passive, non-intrusive method that uses thermal radiation law to determine temperature. It combines electronic and optical instruments to detect low-level signals of radiation measurements. Surface high-temperature measurements are successfully obtained using a two-wavelength pyrometer system. This study used a pyrometer system to achieve high stability, minimize errors due to changing emissivity, and remove background noise from the radiation measurement for surface high-temperature measurements. Temperature measurements were also obtained from Planck’s model, and the results were compared with logarithmic assumption. The precision of these measurements is improved through variable optimization of the instruments, validation of the data, and calibration of the pyrometer system. The 16 temperature measurements were obtained (800–1600°C temperature measurement range) with a correlation coefficient above 97%. The response time between temperature readings is within 785 µs. Furthermore, the high-temperature measurements were obtained with higher stability (±2.99^∘C at 1600°C) and less error (less than 2.29% for Si sensor). In addition, the error of the temperature measurement was reduced from 5.33% to 0.86% at 850°C by using Planck’s model compared with using logarithmic assumption. A cooling system temperature is also optimized to reduce the error temperature reading. It was found to be at 10°C that the uncertainty was reduced from 2.29% at ambient temperature to 1.53% at 1600°C. The spectral pyrometry system was also used in comparison with the two-wavelength pyrometer system to confirm that the calibration curves of the spectral pyrometry can be used to determine temperature measurements.