Guilherme Dutra

Development of NIR optical tomography system for the investigation of two-phase flows

Two-phase flows are present in many processes in nature as well as in industrial activities such as exploration, production and transportation of oil and gas. In many cases, flow monitoring determines the efficiency and safety of processes and equipment. Thus, this paper presents a preliminary study about developing an optical tomography system for real-time monitoring of gas-liquid two-phase flows. The system comprises 16 optical sources and 16 optical receivers operating at near-infrared wavelength. Time response of single channels is optimized allowing for fast frame rate measurements up to 1000 frames/s. Initial tests in a two-phase flow loop show promising results.

Optical imaging of air and water bubbles flowing through oil

The feasibility of optically detecting air and water bubbles flowing through the oil is presented. By scanning wavelengths it is possible to add functionalities by implementing a spectroscopy based chemical detection that can directly lead to chemical detection and imaging and/or chemical species tomography of flowing fluids. In this article, a halogen lamp (175 - 1000 W and centered at 1.2 mm) and an IR-array camera (8-12 μm, 31 x 32 pixels and 10 fps) is used to observe the three-phase flow involving oil, air and water.

Photonic sensors: From horse racing to horse power

The use of photonic sensors to monitor horses is presented and reviewed. Results are very promising and can be used in other areas to monitor animals, machines or industrial processes.

Air Flow Detection in Crude Oil by Infrared Light

In this paper, we used infrared light in the range of 8–12 μm to develop and test an optical imaging system to detect air bubbles flowing in oil. The system basically comprises a broadband light source and a 31 × 32 thermopile array to generate images. To analyze the effects related to light absorption, reflection, and refraction on air-oil boundaries, a numerical model was developed and the predominance of the refraction instead of the absorption in bubbles with diameters below a certain critical value was observed. The IR region of the electromagnetic spectrum has both optical and thermic behavior. To understand the limits of each effect on the oil flow imaging, a study of the influence of temperature variation on the petroleum optical detection was performed. The developed optical imaging system allowed the detection of air flow in static oil and in oil-air two-phase flow. With the presented system, it was possible to achieve images through up to 12 mm of oil volumes, but this may be enhanced by the use of optimized IR sources and detectors.

Large area optical mapping of surface contact angle

Top-down contact angle measurements have been validated and confirmed to be as good if not more reliable than side-based measurements. A range of samples, including industrially relevant materials for roofing and printing, has been compared. Using the top-down approach, mapping in both 1-D and 2-D has been demonstrated. The method was applied to study the change in contact angle as a function of change in silver (Ag) nanoparticle size controlled by thermal evaporation. Large area mapping reveals good uniformity for commercial Aspen paper coated with black laser printer ink. A demonstration of the forensic and chemical analysis potential in 2-D is shown by uncovering the hidden CsF initials made with mineral oil on the coated Aspen paper. The method promises to revolutionize nanoscale characterization and industrial monitoring as well as chemical analyses by allowing rapid contact angle measurements over large areas or large numbers of samples in ways and times that have not been possible before.

Mid-infrared optical tomography for imaging through petroleum: A feasibility study

The feasibility of generating tomographic images of objects inside crude oil is investigated in this paper. Crude oil in the visible spectrum usually appears as black oil. Nevertheless, in the mid-infrared range, crude oil presents bands of high transmission. These windows of opportunities are explored to obtain data for generating cross-section images. In this paper, a first generation tomograph (containing one radiation source and one detector) is setup and applied to visualize objects inside a typical crude oil sample from a Brazilian reservoir. Reconstructed images based on standard filtered back-projection algorithm for phantom measurements show very promising results.

Simple top down imaging measurement of contact angle for practical assessment of hydrophilic surfaces

Top down imaging is used to extract the contact angle, θ, of drops on surfaces greatly relaxing the requirements and limits demanded by side imaging. The method is compared between two standard lateral measurement techniques (the tangent method and the height/diameter method) for the hydrophilic contact angle of a droplet of water (20 drops of 2 μl each) on borosilicate slide: θ= (52 ± 7)° and (52 ± 6)°, respectively, and (53 ± 8)°, for the proposed method, agreeing within experimental error. This technique can be applied on multiple contact angle measurements, depression, between electronic components and on concave surfaces. The top down method has the potential to revolutionize diagnostics by making contact angle measurements ubiquitous and accessible to low cost imaging.