The Experts below are selected from a list of 7401 Experts worldwide ranked by ideXlab platform
Ryuuichirou Yonemoto - One of the best experts on this subject based on the ideXlab platform.
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an investigation on void fraction of vapor liquid two phase flow for smooth and microfin tubes with r134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
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An investigation on void fraction of vapor–liquid two-phase flow for smooth and microfin tubes with R134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
Shigeru Koyama - One of the best experts on this subject based on the ideXlab platform.
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an investigation on void fraction of vapor liquid two phase flow for smooth and microfin tubes with r134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
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An investigation on void fraction of vapor–liquid two-phase flow for smooth and microfin tubes with R134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
Joodong Lee - One of the best experts on this subject based on the ideXlab platform.
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an investigation on void fraction of vapor liquid two phase flow for smooth and microfin tubes with r134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
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An investigation on void fraction of vapor–liquid two-phase flow for smooth and microfin tubes with R134a at Adiabatic Condition
International Journal of Multiphase Flow, 2004Co-Authors: Shigeru Koyama, Joodong Lee, Ryuuichirou YonemotoAbstract:Abstract The present paper deals with experiments and a prediction method for the void fraction of R134a vapor–liquid two-phase flow in horizontal smooth and microfin tubes in Adiabatic Condition. The void fraction is measured by the quick closing valve method. The smooth tube tested is 1024 mm in length and 7.52 mm in inside diameter. The microfin tube tested is 1015 mm in length and 8.86 mm in mean inside diameter; the fin height is 0.18 mm, the helix angle of fins is 25° and the total number of fins are 70. The experiments were carried out in the range of vapor quality from 1% to 96%, where the pressure was kept at 1.2 and 0.8 MPa and the mass flow rate was kept at 20 and 40 kg h−1. It is confirmed that the void fraction for smooth tube is well correlated by the Smith or the Baroczy correlations. It is also shown that the void fraction in the microfin tube is lower than that of smooth tube in any quality and the prediction results using previous correlations for smooth tube are higher than the present experimental data of microfin tube. The void fraction prediction method consisting of a stratified-annular flow model and an annular flow model is proposed. In the stratified-annular flow model, it is assumed that most of liquid flows at the bottom of the tube and all grooves are filled with additional liquid. The momentum equations are constructed for regions of vapor, main liquid flow at the bottom and additional liquid flow in grooves, respectively. These coupled equations are solved numerically. In the case of annular flow model, it is assumed that all grooves are filled with liquid uniformly. The momentum equations in the vapor and liquid flows in grooves are also solved numerically. The values of the predicted void fraction are in good agreement with experimental data in high vapor quality region, while the predicted values are slightly smaller than experimental ones in low vapor quality region.
Qinghai Shu - One of the best experts on this subject based on the ideXlab platform.
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The primary decomposition product of TKX-50 under Adiabatic Condition and its thermal decomposition
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: Junfeng Wang, Shusen Chen, Shaohua Jin, Rui Shi, Chunyuan Zhang, Qinghai ShuAbstract:The primary decomposition product (TKX-50-M) of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) was obtained under Adiabatic Condition by using accelerating rate calorimeter (ARC). Meanwhile, diammonium 5,5′-bistetrazole-1,1′-diolate (ABTOX) was confirmed as the main component of TKX-50-M. Specific heat capacity of TKX-50-M and ABTOX was studied from 0 to 45 °C. In addition, the thermal decomposition of TKX-50-M and ABTOX was studied under Adiabatic Condition. The experiment results revealed that TKX-50-M were more thermal sensitive than ABTOX. Furthermore, ABTOX exhibited much violent than that of TKX-50-M during decomposition.
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thermal hazard assessment of tnt and dnan under Adiabatic Condition by using accelerating rate calorimeter arc
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: Chunyuan Zhang, Shaohua Jin, Baochao Jing, Fang Bao, Guangyuan Zhang, Qinghai ShuAbstract:The thermal decomposition behaviors of 2,4,6-Trinitrotoluene (TNT) and 1-methoxy-2,4-dinitro-benzene (DNAN) were studied by using a NETSCH company accelerating rate calorimetry. Hazard indicators such as onset temperature, Adiabatic temperature rise, initial self-heat temperature, maximum self-heating rate, and time-to-maximum temperature rise rate have been determined directly. The kinetic parameters, such as the activation energy (E a) and the pre-exponential factor (A) were studied from the measured self-heating rate data by assuming order reaction.
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Thermal behavior and thermo-kinetic studies of 5,5′-bistetrazole-1,1′-diolate (1,1-BTO)
Journal of Thermal Analysis and Calorimetry, 2017Co-Authors: Chunyuan Zhang, Shusen Chen, Shaohua Jin, Chang Zhou, Yan Zhang, Qinghai ShuAbstract:Thermogravimetric-differential scanning calorimeter and accelerating rate calorimeter (ARC) were performed to study the thermal characteristics and kinetics of energetic 5,5′-bistetrazole-1,1′-diolate (1,1-BTO). The DSC measurements showed one endothermic peak and one exothermic peak with decomposition occurring at 219.1, 227.2, 234.0 and 244.1 °C at different heating rates (2, 4, 8 and 15 °C min−1). The value of critical temperature of thermal explosion (T b) and kinetics parameters was calculated, suggesting that 1,1-BTO is stable below the temperature of 175.36 °C. The thermal behavior under Adiabatic Condition was studied by ARC, depicting that onset temperature was 176.61 °C and the thermal decomposition ended at 215.93 °C, within the time span of 49.04 min. In addition, the thermo-kinetic parameters such as the activation energy E a and pre-exponential factor A under Adiabatic Condition were also obtained.
Prasanta K. Panigrahi - One of the best experts on this subject based on the ideXlab platform.
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Survival of weak-field seekers inside a TOP trap even beyond the Adiabatic Condition
Modern Physics Letters A, 2019Co-Authors: Nirupam Dutta, Anirban Dey, Prasanta K. PanigrahiAbstract:In this paper, for the first time in the context of time orbiting potential (TOP) trap, the necessary and sufficient Conditions for the Adiabatic evolution of weak field seeking states have been quantitatively examined. It has been well accepted since decades that Adiabaticity has to be obeyed by the atoms for successful magnetic trapping. However, we show, on the contrary, that atoms can also be confined beyond the Adiabatic limit. For the demonstration, we have considered a toy model of a single weak field seeking atom in its ground state and have calculated its survival probability inside a TOP trap. Our findings open new possibilities to relax the restrictions of atom trapping in laboratories.
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Survival of weak-field seekers inside a TOP trap even beyond the Adiabatic Condition
Modern Physics Letters A, 2019Co-Authors: Nirupam Dutta, Anirban Dey, Prasanta K. PanigrahiAbstract:In this paper, for the first time in the context of time orbiting potential (TOP) trap, the necessary and sufficient Conditions for the Adiabatic evolution of weak field seeking states have been qu...