A Rapid Prototyped Thermal Mass Flowmeter

An innovative rapid prototyping technique for embedding microcomponents in PDMS replicas was developed and applied on a thermal mass flowmeter for closed loop micropump flowrate control. Crucial flowmeter design and thermal parameters were investigated with a 3-D fully coupled electro-thermal-fluidic model which was built in Comsol Multiphysics 5.2. The flowmeter was characterized for three distinct measuring configurations. For precise low flowrate applications, a sensor-heater-sensor flowmeter configuration with a constant heater temperature was found to be the most appropriate yielding the measuring range of 0 to 90 µL·min-1 and the sensitivity of 1.3 °C·µL−1·min in the lower flowrate range of 0 to 40 µL·min−1.

Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study, a packed bed reactor was developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor were examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the packed bed with smaller coal size has higher temperature, reaching 624 °C, 582 °C, and 569 °C for coal A, B, and C, respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the packed bed due to different coal particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in underground coal gasification application, as well as temperature to promote the syngas productions.

Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study, a packed bed reactor is developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor are examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the packed bed with smaller coal size has higher temperature, reaching 624oC, 582oC, and 569oC for coal A, B, and C respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the packed bed due to different coal particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in UCG (underground coal gasification) application, as well as temperature to promote the syngas productions.

Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study, a packed bed reactor is developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor are examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the coal packed bed with smaller size has higher temperature, reaching 624 o C, 582 o C, and 569 o C for coal A, B, and C respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the coal packed bed due to different particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in UCG (underground coal gasification) application, as well as temperature to promote the syngas productions.

Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study, a packed bed reactor is developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor are examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the coal packed bed with smaller size has higher temperature, reaching 624oC, 582oC, and 569oC for coal A, B, and C respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the coal packed bed due to different particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in UCG (underground coal gasification) application, as well as temperature to promote the syngas productions.

Experimental investigation and optimization of a low-temperature thermoelectric module with different operating conditions

Purpose This paper aims to present an experimental investigation and optimization of a low-temperature thermoelectric module to examine the influence of the main operating conditions. Design/methodology/approach In this work, a comparison was made by varying the various operating parameters such as heat source temperature, the flow rate of the cold fluid and the external load resistance. A Taguchi method was applied to optimize the parameters of the system. Three factors, including the external load resistance, mass flow rate of water (at the heat sink side) and heater temperature (at the heat source side) along with different levels were taken into account. Analysis of variance was used to determine the significance and percentage contribution of each parameter. Findings The experimental results show that the maximum power output 8.22W and the maximum conversion efficiency 1.11 per cent were obtained at the heater temperature of 240°C, the cold fluid mass flow rate of 0.017 kg/s, module temperature difference of 45°C and the load resistance of 5 O. It was observed that the optimum parameter levels for maximum power output determined as 5 O external load resistance, 0.17 kg/s mass flow rate of water and 240°C heater temperature (A1B3C3). It reflects that these parameters influence on the optimum conditions. The heater temperature is the most significant parameter on the power output of the thermoelectric module. Originality/value It is clear from the confirmation test that experimental values and the predicted values are in good agreement.

An Integrated Method of FVM and SPH for Treating Melting Process of Quartz Ingot

The melting of quartz ingot undergoes solid-liquid phase transition, free-surface, large deformation and other complex flow. Thermal field is the fundamental driving factor during the process. Thus, new method of computing the complex flow and thermal field simultaneously needs to be developed. An integrated method of the finite volume method (FVM) and smoothed particle hydrodynamics (SPH) is proposed to combine the advantages of SPH in the complex flow and FVM in the thermal calculation. The method, a solver conjugate scheme, is implemented through the data exchange between the FVM sub-solver and the SPH sub-solver. The sub-solver of FVM focuses on thermal calculation, and SPH concentrates on complex flow with free-surface and large deformation. The inverse distance weighted (IDW) interpolation and spatial matching are employed to translate data from FVM to SPH and from SPH to FVM separately. The mechanism how the heater temperature affects the thermal field is investigated. The conclusion is that the increasing heater temperature affects the hot zone by raising the sidewalls temperature mainly, thus employing additional heating or cooling ways for controlling the temperature of the sidewalls is an efficient direction to optimize the hot zone design.