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Dive into the research topics where Qiang Liao is active.

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Featured researches published by Qiang Liao.


Chemical Engineering Journal | 2000

Augmentation of convective heat transfer inside tubes with three-dimensional internal extended surfaces and twisted-tape inserts

Qiang Liao; M.D Xin

Experiments were carried out to study the heat transfer and friction characteristics for water, ethylene glycol, and ISO VG46 turbine oil flowing inside four tubes with three-dimensional internal extended surfaces and copper continuous or segmented twisted-tape inserts. During the experiments, Prandtl numbers ranged from 5.5 to 590 and Reynolds numbers from 80 to 50,000. The experimental results show that this compound enhanced heat transfer technique, a tube with three-dimensional internal extended surfaces and twisted-tape inserts, is of particular advantage to enhance the convective heat transfer for the laminar tubeside flow of highly viscous fluid. For the laminar flow of VG46 turbine oil, the average Stanton number could be enhanced up to 5.8-fold inside tubes with three-dimensional internal extended surfaces and continuous twisted-tape inserts compared with an empty smooth tube, and the friction factor was also increased by almost 6.5-fold. Inside the tubes with three-dimensional internal extended surfaces, replacement of the continuous twisted-tape inserts with the segmented twisted-tape inserts induced a greater decrease in the friction factor but a comparatively smaller decrease in the Stanton number.


Bioresource Technology | 2010

Characteristics of a biofilm photobioreactor as applied to photo-hydrogen production.

Xin Tian; Qiang Liao; Xun Zhu; Yongzhong Wang; Pan Zhang; Jun Li; Hong Wang

The application of a cell immobilization technique to a biofilm-based photobioreactor was developed to enhance its photo-hydrogen production rate and light conversion efficiency. Rhodopseudomonas palustris CQK 01 was initially attached to the surface of packed glass beads to form a biofilm in this experiment. Then, the biofilm photobioreactor (BPBR) was illuminated by light-emitting diodes with light wavelengths of 470, 590 and 630 nm and hydrogen was evolved with glucose being the sole carbon source. Under the illumination condition of 5000 lux illumination intensity and 590 nm wavelength, the BPBR showed good hydrogen production performance: the hydrogen production rate was 38.9 ml/l/h and light conversion efficiency was 56%, while the hydrogen yield was 0.2 mol H(2)/ mol glucose. Furthermore, results show that the highest hydrogen production rate and glucose removal rate were obtained when the glucose concentration is 0.12 M, the optimal pH 7 and optimal temperature of influent liquid 25 degrees C.


Bioresource Technology | 2010

Characteristics of hydrogen production and substrate consumption of Rhodopseudomonas palustris CQK 01 in an immobilized-cell photobioreactor

Yongzhong Wang; Qiang Liao; Xun Zhu; Xin Tian; Chuan Zhang

Effects of operation parameters on hydrogen production rate, substrate utilization efficiency and hydrogen bioconversion yield were investigated in a photobioreactor packed with sodium alginate/polyvinyl alcohol-124/carrageenan granules containing Rhodopseudomonas palustris CQK 01. Results demonstrate that an increase in influent glucose concentration and flow rate enhanced glucose transport from the bulk liquid into the granules, resulting in high hydrogen production. The bacteria mainly utilized the photo-heterotrophic pathway under optimal light illumination and produced hydrogen at low influent substrate loading, while they produced organic acids at high influent loading. The optimal temperature and pH of the influent medium for hydrogen production were independent of the illumination wavelength. The maximal hydrogen production rate of 2.61mmol/L/h was achieved under illumination at 590nm and 6000lx, a substrate concentration of 60mmol/L, a temperature of 30 degrees C and a pH7 of the influent medium.


Bioresource Technology | 2010

Formation and hydrogen production of photosynthetic bacterial biofilm under various illumination conditions

Qiang Liao; Ye-Jun Wang; Yongzhong Wang; Xun Zhu; Xin Tian; Jun Li

The application of immobilized-cell technology in photobioreactor for hydrogen production could offer improvements in photo-hydrogen production rate and light utilization efficiency. Indigenous Rhodopseudomonas palustris CQK 01 was attached to the surface of a cover glass slide in a flat-panel photobioreactor, to form biofilm under illumination with a range of intensities and wavelengths. The morphology and structure of mature photosynthetic bacterial (PSB) biofilm were determined to elucidate the relationship between biofilm formation and hydrogen production performance. The effects of operation conditions on hydrogen production performance of the biofilms formed under various illumination conditions were experimentally investigated. The results showed that illumination wavelength and intensity substantially influenced the morphology and structure of the biofilm, and the hydrogen production performance of mature biofilm varied significantly with the illumination conditions that were used for biofilm formation. Biofilm formed under 590 nm and 5000 lx illumination showed the highest hydrogen production performance.


Bioresource Technology | 2014

A novel photobioreactor generating the light/dark cycle to improve microalgae cultivation

Qiang Liao; Lin Li; Rong Chen; Xun Zhu

In this work, a novel tubular photobioreactor with the outer surface periodically shaded by the light-shielding material at pre-set interval was developed. Such design forms periodic light and dark regions along tubular photobioreactor, which creates controllable light/dark cycle and favours the microalgae growth. Experimental results showed that the developed photobioreactor was beneficial for the growth of Chlorella pyrenoidosa and a higher light-to-biomass conversion efficiency was achieved. The effects of the frequency of the light/dark cycle and light intensity on the microalgae cultivation were also investigated. It was revealed that this new design could greatly enhance the photosynthetic efficiency. As compared to conventional photobioreactors, the average biomass productivity could be increased by 21.6±2.1% when the frequency of created artificial light/dark cycle was set at 100Hz. The photobioreactor developed in this work enables an efficient light-to-biomass conversion and provides a viable and promising vision for large-scale outdoor applications.


Bioresource Technology | 2011

Enhancement of photo-hydrogen production in a biofilm photobioreactor using optical fiber with additional rough surface.

Cheng-Long Guo; Xun Zhu; Qiang Liao; Yongzhong Wang; Rong Chen; Duu-Jong Lee

In this study, a biofilm photobioreactor with optical fibers that have additional rough surface (OFBP-R) was developed and it was shown that additional rough surface greatly enhanced the biofilm formation and thus increased the cell concentration, leading to an improvement in the hydrogen production performance. The effects of operational conditions, including the influent substrate concentration, flow rate, temperature and influent medium pH, on the performance of OFBP-R were also investigated. The experimental results showed that the optimum operational conditions for hydrogen production were: the influent substrate concentration 60 mM, flow rate 30 mL/h, temperature 30 °C and influent medium pH 7. Under the optimal operation conditions discovered in this work, the OFBP-R yielded fairly good and stable long-term performance with hydrogen production rate of 1.75 mmol/L/h, light conversion efficiency of 9.3% and substrate degradation efficiency of 75%.


Bioresource Technology | 2016

Kinetic characteristics and modeling of microalgae Chlorella vulgaris growth and CO2 biofixation considering the coupled effects of light intensity and dissolved inorganic carbon.

Hai-Xing Chang; Yun Huang; Qian Fu; Qiang Liao; Xun Zhu

Understanding and optimizing the microalgae growth process is an essential prerequisite for effective CO2 capture using microalgae in photobioreactors. In this study, the kinetic characteristics of microalgae Chlorella vulgaris growth in response to light intensity and dissolved inorganic carbon (DIC) concentration were investigated. The greatest values of maximum biomass concentration (Xmax) and maximum specific growth rate (μmax) were obtained as 2.303 g L(-1) and 0.078 h(-1), respectively, at a light intensity of 120 μmol m(-2) s(-1) and DIC concentration of 17 mM. Based on the results, mathematical models describing the coupled effects of light intensity and DIC concentration on microalgae growth and CO2 biofixation are proposed. The models are able to predict the temporal evolution of C. vulgaris growth and CO2 biofixation rates from lag to stationary phases. Verification experiments confirmed that the model predictions agreed well with the experimental results.


Nanoscale and Microscale Thermophysical Engineering | 2006

Gas Flow in Microchannel of Arbitrary Shape in Slip Flow Regime

Xun Zhu; Qiang Liao; Mingdao Xin

A theoretical analysis for laminar flow in the microchannels of arbitrary shape in slip flow regime is presented in this article. The momentum equations with the first-order slip, the second-order slip, and the thermal creep flow boundary conditions are solved by applying a computation-oriented method of the orthonormal function analysis for the fully developed laminar flow of the incompressible fluid in the microchannels. The dimensionless velocity profile and the friction factor are theoretically predicted for a microchannel of arbitrary shape. To justify the methodology, the friction factor of gas flowing in the rectangular microchannel is calculated and compared with the experimental data. The good agreement between analytic solutions and experimental data shows that within a definite extension of Knudsen number, the traditional Navier–Stokes equations with the slip boundary conditions can govern the gaseous slip flow mechanisms in microchannels, and the orthonormal function method is applicable to solve the momentum equation with the slip flow boundary condition in the microchannel of arbitrary shape. It is found from the theoretical predictions that the slip velocity of fluid on the microchannel wall increases as the Kn number increases, and the friction coefficient is substantially smaller for slip flow compared with the no-slip flow. The aspect ratio of a microchannel has a remarkable effect on the dimensionless drag coefficient at a fixed Kn number in the rectangular microchannels. The friction coefficient for the second-order slip boundary condition is greater than that for the first-order slip boundary condition, and the thermal creep flow on the microchannel wall tends to increase the friction coefficient in the microchannel.


ACS Applied Materials & Interfaces | 2013

Optofluidic Microreactors with TiO2-Coated Fiberglass

Lin Li; Rong Chen; Xun Zhu; Hong Wang; Yongzhong Wang; Qiang Liao; Dongye Wang

Optofluidic microreactors are promising prospects for photocatalytic reactions. However, because the flow type in conventional designs is typically laminar, the mass transport mainly relies on diffusion, and thus the rate of mass transport is limited. Accordingly, poor mass transport reduces the photocatalytic reaction rate. To alleviate the limitation of mass transport, in this work, we proposed a novel optofluidic microreactor with TiO2-coated fiberglasses immersed in the microreaction chamber. Such a design enables enhanced mass transport by shortening the transport length and inducing the perturbation to liquid flow so as to improve the performance. We demonstrated the feasibility of the optofluidic microreactor with the TiO2-coated fiberglass by the photocatalytic water treatment of methylene blue under UV irradiation. Results showed that the proposed optofluidic microreactor yielded much higher degradation efficiency than did the conventional optofluidic microreactor as a result of enhanced mass transport. The microreactor with the TiO2-coated fiberglass showed a 2-3-fold improvement in the reaction rate constant as opposed to conventional ones. The maximal increment of the degradation efficiency can reach more than 40%.


Journal of Materials Chemistry | 2016

A three-dimensional nitrogen-doped graphene aerogel-activated carbon composite catalyst that enables low-cost microfluidic microbial fuel cells with superior performance

Yang Yang; Tianyu Liu; Qiang Liao; Dingding Ye; Xun Zhu; Jun Li; Pengqing Zhang; Yi Peng; Shaowei Chen; Yat Li

Microfluidic microbial fuel cells (μMFCs) are promising miniaturized power generators and bio-sensors, which combine the micro-fabrication process with bio-chip technology. However, a limited power output and considerable cost severely restrict their practical applications. Previous research has revealed that inadequate colonization of bacteria on bio-anodes as well as sluggish oxygen reduction reaction (ORR) kinetics are two main causes for the unsatisfactory power output. In this study, we have demonstrated a μMFC that has successfully addressed the aforementioned limitations by utilizing low-cost self-assembled reduced graphene oxide–nickel (rGO@Ni) foam and a nitrogen-doped graphene aerogel-activated carbon (AC@N-GA) as the bio-anode and air-cathode electrodes, respectively. The three-dimensional and macro-porous structure of the rGO@Ni foam provides a large surface area for bacterial colonization and hence largely increases the loading amount of bacterial cells. The AC@N-GA electrode shows excellent ORR catalytic performance due to the meso-porous structure and the presence of nitrogen functionalities that can serve as the catalytic sites. As a result, the μMFC achieves a maximum power density of 1181.4 ± 135.6 W m−3 (continuous-mode) and 690.2 ± 62.3 W m−3 (batch-mode) evaluated based on the volume of the reactor (50 μL). To our knowledge, this is the highest volumetric power density reported for air-breathing μMFCs and microfluidic glucose fuel cells with a similar configuration. Besides, the utilization of the inexpensive electrodes and membrane-free architecture could significantly decrease the fabrication cost of μMFCs.

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Xun Zhu

Chongqing University

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Jun Li

Chongqing University

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Qian Fu

Chongqing University

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