Dr. Luai M.
Al-Hadhrami
CENTER FOR
Engineering Research
Papers in Refereed Journals
1. Luai M. Al-Hadhrami, “Study of Heat Transfer Distribution in a Channel with Inclined Target Surface Cooled by Single Array of Staggered Impinging Jets, Heat Transfer Engineering Journal (90145-7632). Accepted (2009).
2. Luai M. Al-Hadhrami “Effect of Feed Channel Width on Heat Transfer in a Rectangular Duct with an Array of Off-set Jets”, ASME Turbo Expo 2006 Power for Land, Sea and Air, Barcelona, Spain 8-11 May 2006.
3. Griffith, T., Al-Hadhrami, L., and Han, J. C. "Heat transfer in rotating rectangular cooling channels (AR=4) with angled ribs". Journal of Heat Transfer 124, 617-625 (2002).
4. Griffith, T., Al-Hadhrami, L., and Han, J. C., Heat transfer in rotating rectangular cooling channels (AR=4) with dimples. Journal of Turbomachinery Transactions of the ASME. 125 (3): 555-563 Jul 2003.
5. R.Ban-Mansour, and L. Al-Hadhrami, “Effect of Reynolds number and property variation on fluid flow and heat transfer in the entrance region of a turbine blade internal-cooling channel” International Journal of Rotating Machinery 2005: RI 36-44, Hindawi Publisher Corporation.
6. H.M. Tawancy and Luai M. Al-Hadhrami, “Applications of microstructural characterization and computational modeling in damage analysis of a turbine blade exposed to service conditions in a power plant”, Engineering Failure Analysis Journal, 15 (2008) 1027-1034.
7. H.M. Tawancy and Luai M. Al-Hadhrami, “Degradation of turbine blades and vanes by overheating in a power station”, Engineering Failure Analysis Journal, 16 (2009) 273-280.
8. H.M. Tawancy and Luai M. Al-Hadhrami, “Failure of refurbished turbine blades in a power station by improper heat treatment”, Engineering Failure Analysis Journal, 16 (2009) 810-815.
9. Luai M. Al-Hadhrami and A. Ahmad, “Assessment of Thermal Performance of different types of masonry bricks used in Saudi Arabia”, Applied Engineering Journal, 29 (2009) 1123-1130.
10. H.M. Tawancy and Luai M. Al-Hadhrami, “Failure analysis of a welded outlet manifold pipe in a primary steam reformer by improper selection of materials”, Engineering Failure Analysis Journal, 16 (2009) 810-815.
11. Al-Hadhrami, L., and Han, J. C., "Effect of rotation on heat transfer in two-pass square channels with five different orientations of 45 deg. angled rib turbulators" International Journal of Heat and Mass Transfer, 46 (2003) 653-669.
12. Al-Hadhrami, L., Griffith, T., and Han, J. C., “Heat transfer in two-pass rotating rectangular channels (AR=2) with five different orientations of 45 Deg.V-shaped rib turbulators”,. Journal of Heat Transfer, Vol. 125, 232-242, 2003.
Refereed Conference Papers
13. Ali-Mubarak, A.A., S.M. Shaahid and Luai M. Al-Hadhrami (2008). “Effect of orifice jet configuration on heat transfer in a channel with inclined target surface cooled by single array of impinging jets with outflow in both directions. 2008 Proceedings of the ASME Micro/Nanoscale Heat Transfer Onternational Conference, MNHT 2008 PART B, pp. 825-834 Tainan, Taiwa.
14. Mehboob Basha and Luai M. Al-Hadhrami, (2008). “Heat Transfer in a Channel with Inclined Target Surface Cooled by Single Array of Impinging Jets”. Proceedings of ASME Turbo Expo 2007 Power for Land, Sea, and Air. May 14-17, 2007, Montreal, Canada.
15. Al-Hadhrami, L.M., S.M. Shaahid and Ali A. Al-Mubarak. “Heat Transfer in a Channel with Inclined Target Surface Cooled by Single Array of Impinging Jets”. Proceedings of ASME Turbo Expo 2007 Power for Land, Sea, and Air. May 14-17, 2007, Montreal, Canada.
16. Tawancy, H.M. and Luai M. Al-Hadhrami. “Applications of Microstructural Characterization and Computational Modeling in Damage Analysis of A Turbine Blade Exposed to Service Conditions in a Power Plant.” Proceedings of ASMETurbo Expo 2007 Power for Land, Sea, and Air. May 14-17, 2007, Montreal, Canada.
17. Luai M. Al-Hadhrami, S.M. Shaahid and Mirza Zaheer Baig, “Design and Operation of a Fouling Monitoring Device”, Heat Exchanger Fouling and Cleaning – VII, July1-6, 2007, Hotel dos templarios, Tomar, Portugal.
18. Luai Al-Hadhrami, M. Basha, “Numerical Fluid Flow and Heat Transfer Prediction of Rotating Tapered Channel”, 5th International Conference On Computational Heat and Mass Transfer, Canmore, Canada, June, 18-22, 2007.
19. Al-Hadhrami, Luai M., S. M. Shaahid, and Ali Mubarak (2007). Effect of orifice jet configuration on heat transfer characteristics in a channel with inclined target surface cooled by single array of impinging jets with outflow parallel to entry flow. International Gas Turbine Conference (IGTC’07) 2007, 2-7 December, Tokyo, Japan.
20. Luai M. Al-Hadhrami (2006). “Effect of Feed Channel Width on Heat Transfer in a Rectangular Duct with an Array of Off-set Jets”, ASME Turbo Expo 2006 Power for Land, Sea and Air, Barcelona, Spain 8-11 May 2006.
21. Al-Hadhrami, Luai M.(2006) Effect of Feeding Channel Aspect Ratio and Orifice Jet Configuration on Heat Transfer in a Rectangular Channel, Proceedings of the 2nd International Conference on Thermal Engineering Theory and Applications January 3 - 6, 2006, Al Ain, United Arab Emirates
22. Luai Al-Hadhrami (2006) “Effect of Feed Channel Aspect Ratio and Orifice Jet Configuration on Heat Transfer in a Rectangular Channel”, International Heat Transfer Conference IHTC-13, Sydney-NSW-Australia-13, 18 August 2006.
23. Luai Al-Hadhrami (2006) Author from Dr. Luai Experimental Heat Transfer on a Heated Target Surface Using Centreline Impingement Jets in a Rectangular Duct., The Seventeenth International Symposium on Transport Phenomena, 4-8 September, 2006, Toyama, JAPAN.
24. Maher Shariff, and Luai, Al-Hadhrami, “Numerical Modeling of Heat Transport Enhancement in Dimpled Rectangular Turbine Cooling Channels”, 4th International Conference on Computational Heat and Mass Transfer, Praise- France 2005
25. M. Basha, M. Al-Qahtani, and L. Al-Hadhrami, “Flow and Temperature Distribution in Rotating One-Pass Pin-Finned Channel”, Proceeding of the International Conference on Recent Advances in Mechanical Engineering, 30-31 May 2005, Kuala Lumpur, Malaysia, Paper No. 273
26. Al-Hadhrami, L M., and R. Bin-Mansor, "Effect of entrance geometry on fluid flow and heat transfer in one pass Smooth isothermally heated channel", The 14th International Symposium on Transport Phenomena, page 197-202, 6-9 July 2003, Balik, Indonesia.
27. R. Ben-Mansour and L. Al-Hadhrami, “Fluid flow and heat transfer in a turbine internal-cooling channel and its entrance region, “The first international exergy, energy, and environment system, pp. 207-213, 13-17 July 2003, Izmir-Turkey.
28. Al-Hadhrami, L M., Griffith, T., and Han, J. C. Heat transfer in two-pass rotating rectangular channels (AR=2) with parallel and crossed 45o V-shaped rib turbulators. 40th AJAA Aerospace Sciences Meeting & Exhibit, 14-17 January 2002, Reno, Nevada, USA.
29. Griffith, T., Al-Hadhrami, L.M., and Han, J. C. Heat transfer in rotating rectangular cooling channels (AR=4) with dimples. Proceedings of ASME Turbo Expo 2002, June 3-6, 2002, Amsterdam, Netherlands.
30. Al-Hadhrami, L M., and K. Ahmed “Effect of Outflow Orientation and Orifice Jet Size on a Heated Surface in a Rectangular Duct using Jet Impingement Technique”, 6th World Conference on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics. 17-21 April 2005 Matsushima, Miyagi, Japan.
31. Griffith, T., Al-Hadhrami, L.M., and Han, J. C. Heat transfer in rotating rectangular cooling channels with angled ribs. 35th AIAA Thermophysics Conference, 11-14 June 2001, Anaheim, CA, USA
Selected Publications
The selected papers represent the areas of research that I have been involved.
1. Luai M. Al-Hadhrami, “Study of Heat Transfer Distribution in a Channel with Inclined Target Surface Cooled by Single Array of Staggered Impinging Jets”, Heat Transfer Engineering Journal, 2009, Accepted.
An experimental investigation has been carried out to study the heat transfer characteristics in a channel with a heated target surface inclined at an angle, cooled by a single array of staggered impinging jets. The work encompasses the effect of three feed channel aspect ratios (5,7,9) and three exit outflow orientations (coincident with the entry flow, opposed to the entry flow, and both), and three Reynolds numbers (9400, 14400, 18800) on heat transfer. Results show that increasing the Reynolds number increases the heat transfer on the inclined target surface. The outflow orientations affect significantly the local heat transfer characteristics, through influencing the jet flow together with the cross flow in the impingement channel. The outflow orientation coincident with the entry flow, and outflow from both sides show better averaged Nusselt number values compared to outflow orientation opposed to the entry flow. The inclined surface affects the local Nusselt number distribution especially for the outflow orientation opposing the entry flow at the narrow region of the impingement channel. In general, the feed channel aspect ratio does not affect the Nusselt number distribution, except for outflow coincident with the entry flow. The local Nusselt number for aspect ratio 9 has been found to be greater than the Nusselt number for aspect ratio 5 by 11%. Additionally, for a given jet-orifice plate with staggered holes, the heat transfer is almost the same throughout the target surface for the outflow exiting in both directions.
2. Luai M. Al-Hadhrami “Effect of Feed Channel Width on Heat Transfer in a Rectangular Duct with an Array of Off-set Jets”, ASME Turbo Expo 2006 Power for Land, Sea and Air, Barcelona, Spain 8-11 May 2006.
Experimental investigation was carried out to study the heat transfer characteristics in a rectangular duct cooled by an array of impinging jets. Air ejected from an array of orifices is aimed at the heated target surface and exits from the radial outlets. The effect of feed channel widths (5≤H/d4≤9), jet to target plate distance (4≤S/d≤8), outflow orientation and jet Reynolds numbers (9300≤Re≤18800), with a single array of equally spaced off-set orifice jets of diameter d = 0.5 cm on heat transfer was studied. Results indicated that the outflow orientation causing cross flow effect significantly affects the Nusselt number distributions on the target surface. Relatively higher Nusselt number values were obtained for the outflow orientation where the flow exits in both the directions. The feed channel width H/d=7 gave relatively higher values of heat transfer compared to the other two feed channel widths. The jet-to-plate distance S/d=4 resulted in higher heat transfer compared to the other jet-to-plate distances.
3. Griffith, T., Al-Hadhrami, L., and Han, J. C. "Heat transfer in rotating rectangular cooling channels (AR=4) with angled ribs", Journal of Heat Transfer 124, 617-625 (2001).
An investigation into determining the effect of rotation on heat transfer in a rib-roughened rectangular channel with aspect ratio of 4:1 is detailed in this paper. A broad range off low parameters have been selected including Reynolds number (Re=5000–40000), rotation number (Ro=0.04–0.3) and coolant to wall density ratio at the inlet (Δρ/ρ)i=0.122. The rib turbulators, attached to the leading and trailing surface, are oriented at an angle (α=45) deg! to the direction of flow. The effect of channel orientations of β=90 deg and 135 deg with respect to the plane of rotation is also investigated. Results show that the narrow rectangular passage exhibits a much higher heat transfer enhancement for the ribbed surface than the square and 2:1 duct previously investigated. Also, duct orientation significantly affects the leading and side surfaces, yet does not have much affect on the trailing surfaces for both smooth and ribbed surfaces. Furthermore, span-wise heat transfer distributions exist across the leading and trailing surfaces and are accentuated by the use of angled ribs. The smooth and ribbed case trailing surfaces and smooth case side surfaces exhibited a strong dependence on rotation number.
4. Griffith, T., Al-Hadhrami, L., and Han, J. C. Heat transfer in rotating rectangular cooling channels (AR=4) with dimples. Journal of Turbomachinery Transactions of the ASME. 125 (3): (July 2003), 555-563.
As the world of research seeks ways of improving the efficiency of turbo machinery, attention has recently focused on a relatively new type of internal cooling channel geometry, the dimple. Preliminary investigations have shown that the dimple enhances heat transfer with minimal pressure loss. An investigation into determining the effect of rotation on heat transfer in a rectangular channel (aspect ratio = 4:1) with dimples is detailed in this paper. The range of flow parameters includes Reynolds number (Re=5000–40000), rotation number (Ro=0.04–0.3) and inlet coolant-to-wall density ratio ((Δρ/ρ=0.122.). Two different surface configurations are explored, including a smooth duct and dimpled duct with dimple depth-to-print diameter (δ/Dρ) ratio of 0.3. A dimple surface density of 10.9 dimples/in2 was used for each of the principal surfaces (leading and trailing) with a total of 131 equally spaced hemispherical dimples per surface; the side surfaces are smooth. Two channel orientations of β=90 and 135 deg with respect to the plane of rotation are explored to determine channel orientation effect. Results show a definite channel orientation effect, with the trailing-edge channel enhancing heat transfer more than the orthogonal channel. Also, the dimpled channel behaves somewhat like a 45 deg angled rib channel, but with less span wise variations in heat transfer.
5. R.Ban-Mansour, and L. Al-Hadhrami, “Effect of Reynolds number and property variation on fluid flow and heat transfer in the entrance region of a turbine blade internal-cooling channel”, International Journal of Rotating Machinery 1(2005): 36-44.
Internal cooling is one of the effective techniques to cool turbine blades from inside. This internal cooling is achieved by pumping a relatively cold fluid through the internal-cooling channels. These channels are fed through short channels placed at the root of the turbine blade, usually called entrance region channels. The entrance region at the root of the turbine blade usually has a different geometry than the internal-cooling channel of the blade. This study investigates numerically the fluid flow and heat transfer in one-pass smooth isothermally heated channel using the RNG k−ε model. The effect of Reynolds number on the flow and heat transfer characteristics has been studied for two mass flow rate ratios (1/1 and 1/2) for the same cooling channel. The Reynolds number was varied between 10,000 and 50,000. The study has shown that the cooling channel goes through hydrodynamic and thermal development which necessitates a detailed flow and heat transfer study to evaluate the pressure drop and heat transfer rates. For the case of unbalanced mass flow rate ratio, a maximum difference of 8.9% in the heat transfer rate between the top and bottom surfaces occurs at Re=10,000 while the total heat transfer rate from both surfaces is the same for the balanced mass flow rate case. The effect of temperature-dependent property variation showed a small change in the heat transfer rates when all properties were allowed to vary with temperature. However, individual effects can be significant such as the effect of density variation, which resulted in as much as 9.6% reduction in the heat transfer rate.
6. H.M. Tawancy and Luai M. Al-Hadhrami “Applications of microstructural characterization and computational modeling in damage analysis of a turbine blade exposed to service conditions in a power plant”, Engineering Failure Analysis Journal, 15 (2008) 1027-1034.
Micro-structural characterization and computational modeling were used to analyze the damage produced by overheating of a turbine blade exposed to service conditions in a power plant. Various electron-optical techniques were used to characterize the microstructure. Localized overheating was reflected by the micro structural features of the blade material particularly the extent of inter diffusion between the coating and alloy substrate, coarsening of the γ-phase, and re-precipitation of M23C6 carbide by a discontinuous mechanism at grain boundaries. Damage associated with these effects included creep cavities at grain boundaries and inter granular oxidation leading to ductile inter granular cracking at the leading edge of the blade. Most evidence pointed out that improper internal cooling of the blade resulted in excessive overheating at leading edge. Qualitatively, the temperature profile across the blade as indicated by micro structural variations was consistent with the results derived from computational modeling.
7. H.M. Tawancy and Luai M. Al-Hadhrami “Degradation of turbine blades and vanes by overheating in a power station”, Engineering Failure Analysis Journal, 16 (2009) 273-280.
First-stage turbine blades and vanes were fractured after 18,420 h of operation at about 800 oC in a power station. Overheating was found to be the cause of failure as indicated by micro structural characterization using various electron-optical techniques. This was indicated by coarsening and rafting of the strengthening γ-phase in the nickel-base blade material as well as the presence of a continuous network of grain boundary carbides. For the cobalt-base vane material, overheating was indicated by decomposition of MC-type carbides and formation of a cellular structure of Laves phase at grain boundaries. Fracture of both the blades and vanes was found to occur by a mixed mode involving inter granular cracking and fatigue. Most evidence pointed out that initial damage by creep resulting in inter granular cracking had shortened the fatigue life of blades and vanes.
8. H.M. Tawancy and Luai M. Al-Hadhrami “Failure of refurbished turbine blades in a power station by improper heat treatment”, Engineering Failure Analysis Journal, 16 (2009) 810-815.
Turbine blades in a power station exposed to a temperature of about 800 oC were refurbished after 40,000 h of operation. However, after only 900 h of service at the same temperature, a number of refurbished blades were fractured. Various electron microscopy techniques as well as computational modeling were used to develop a one-to-one correspondence between microstructure and temperature distribution. Fracture was found to occur by a ductile inter granular mode. Although there was no evidence for overheating during service, the results showed that the blades initially contained γ precipitate-free zones alongside grain boundaries, which could accelerate inter granular failure consistent with the observed fracture mode. It was concluded that the blades were damaged by improper heat treatment during refurbishing.
9. Luai M. Al-Hadhrami and A. Ahmad “Assessment of Thermal Performance of different types of masonry bricks used in Saudi Arabia”, Applied Engineering Journal, 29 (2008) 1123-1130.
This paper presents the assessment of thermal performance of nine types of clay brick and two types of concrete brick in use in Saudi Arabia. The results are based on the experimentally measured values of equivalent thermal conductivity. The analysis of the measured data showed that the addition of insulation material either within the masonry brick mix to make the brick more lightweight or through filling insulation material into the holes of masonry bricks increases the thermal resistance significantly. Red clay brick were found more thermally effective than concrete brick. Use of insulating mortar in building walls increases the thermal resistance compared to that of the walls prepared with ordinary concrete mortar. An economic analysis shows that the insulated clay brick (type 7) is the most effective among the types of brick studied as it has the lowest net present value (NPV) of 36.9 $/m2. The load due to thermal transmission through a building envelope (walls and roof) constitutes an appreciable percent a building’s total thermal load. Therefore, long-term studies of the thermal performance of building materials should be conducted to establish thermally optimal brick for usage in building construction in the Kingdom of Saudi Arabia.
10. H.M. Tawancy and Luai M. Al-Hadhrami, “Failure analysis of a welded outlet manifold pipe in a primary steam reformer by improper selection of materials”, Applied Engineering Journal, 16 (2009) 816-824.
A welded manifold pipe in a primary steam reformer used to transport hydrogen gas at about 873oC developed leakage in the weld fusion zone after about 22,000h of operation. Detailed microstructural characterization using various electron-optical techniques and mechanical property evaluation were employed to determine the cause of failure. Selection of pipe material and filler metal with relatively high Si contents in the presence of Nb was found to be the cause of failure. It is shown that this combination had promoted intergranular precipitation of the embrittling Ni3Nb2Si Laves phase in the weld fusion zone leading to loss of rupture ductility and associated cracking
