Study on heat efficiency of laser-TIG double-side welding

A series of laser-TIG double-side welding experiments for aluminum alloys were carried out to investigate the heat efficiency of the process. The melting efficiency was introduced to evaluate quantitatively the degree of the mutual effect of the laser and the arc. The results showed that the melting efficiency of laser-TIG double-side welding exceeded the sum of the laser and the arc taken separately. With the increase of heat input, the weld depth and melting efficiency of the laser and the arc were increased signifwantly. This, in fact, implies the strong mutual effect of the laser and the arc as heat sources joined simultaneously in the process. Comparatively, the higher efficiency of the laser constituent of heat sources plays the main role in the increase of the process efficiency. The phenomena of arc column convergence, increased laser absorptivity and the formation of heat accumulation region are the causes of the improvement of heat efficiency.

A Cogeneration System for an Apartment Building Based on Distributed Heat Storage Technology

In order for economically viable distributed generation systems for apartment buildings to spread, it is essential to develop an efficient and low-cost heat supply system. We have developed a new eogeneration system called the Neighboring Cogeneration system （NCG）. The key concept of this system is to install a heat accumulator with a hot water supply and a room heating function at each household and to connect different households by a single loop of hot water pipe. As a result, time leveling of the heat supply and heat transferring among households becomes possible. Thus, the costs of the pipe and the heat source equipment decrease. Furthermore, because all of the heat accumulators store heat, the total heat storage capacity is large enough for cogeneration to generate exhaust heat according to the electricity demand and with a high operating rate. In this paper, we report the results of the NCG system for 7 lived-in households. The controlling system worked efficiently. All of the households were able to use hot water without any difficulties. Further, we report the results of the energy saving effect of the NCG system for 50 lived-in households by means of a simulation based on the experimental results for NEXT21.

Performance Evaluation Methods for Multi-stream Plate-Fin Heat Exchanger

Mathematical model of cross type multi-stream plate-fin heat exchanger is established.Meanwhile,mean square error of accumulative heat load is normalized by dimensionless,and the equations of temperature-difference uniformity factor are improved.Evaluation factors above and performance of heat exchanger are compared and analyzed by taking aircraft three-stream condenser as an example.The results demonstrate that the mean square error of accumulative heat load is common result of total heat load and excess heat load between passages.So it can be influenced by passage arrangement,flow inlet parameters as well as flow patterns.Dimensionless parameter of mean square error of accumulative heat load can reflect the influence of passage arrangement to heat exchange performance and will not change dramatically with the variation of flow inlet parameters and flow patterns.Temperature-difference uniformity factor is influenced by passage arrangement and flow patterns.It remains basically unchanged under a certain range of flow inlet parameters.

Thermal performances of non-equidistant helical-coil phase change accumulator for latent heat storage

Helical-coil is a common structure of heat exchanger unit in phase change heat accumulator and usually has the equal coil pitch between adjacent coils. Its thermal performances could be improved by improving the uniformity of the phase change material （PCM） temperature distribution. Thus, a novel non-equidistant helical-coil structure was proposed in this study. Its coil pitch decreased along the flow direction of heat transfer fluid, which made the heat exchange area in unit volume increase to match the decreasing temperature difference between the heat transfer fluid and PCM. The structure was optimized using numerical simulation. An experimental system was developed and the experiment results indicated that the proposed non-equidistant helical-coil heat accumulator was more effective than equidistant helical-coil for latent heat storage. The uniformity of the temperaalre distribution was also confirmed by simulation results.

The effect of spherical aberration on temperature distribution inside glass by irradiation of a high repetition rate femtosecond pulse laser

In this paper, we study the effect of spherical aberrations on the light intensity and the temperature distribution in the focal region in a 250-kHz femtosecond laser irradiated Ag^＋-doped borosilicate glass. When a focused beam goes through an interface between air and glass, spherical aberration will result in the separation of the focal point and then cause a clear change of the light intensity distribution along the incident direction. That phenomenon will further influence the longitudinal cross-section temperature distribution in glass. Here we use Ag nanoparticle formation as a marker for establishing temperature distribution and we find that the formation of nanoparticle shows a strong dependence on the temperature field and the detailed precipitation process is also discussed.

Genetic model and exploration target area of geothermal resources in Hongtang Area, Xiamen, China

The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature.To better understand the whole process and conditions of heat control in the middle and deep crust,this study focuses on the analysis of heat accumulation model in Hongtang Area of Xiamen,and the main conditions of the model such as faults and sags are explored and interpreted in detail by using gravity and wide-field electromagnetic methods.4 main faults(F33,F2,F12 and HT-F1)and 10 secondary faults(HT-F2,HT-F3,HT-F4,HT-F5,HT-F6,HT-F7,HT-F8,HT-F9,HT-F10 and HT-F11)were inferred,and the distribution range of sags was delineated.The convective geothermal system is composed of four components:Heat source,geothermal reservoir,heat-conductive fault and heat retaining cover,which form a quaternary heat accumulation model.According to the model,the intersection of the main faults F12,HTF1 and F33 can be delineated as the primary target area of geothermal exploration,while the intersection of the secondary faults(F12 and HT-F6;F12 and HT-F2;HT-F9,HT-F10 and F12;F12 and HT-F11;F33 and HT-F3;HT-F8 and HT-F3;HT-F2,HT-F10 and HT-F1)can be delineated as the secondary target area.Borehole DR01,which is located in the primary target area,shows that the water temperature increases from fast to slow in the depth range of 0–500 m,and stays at 36℃below 500 m.The reliability of the heat accumulation model and the target area was tested via geothermal boreholes,which is of great significance to the exploitation and utilization of geothermal resources in Hongtang Area of Xiamen.

Lower fuel consumption model and air-flow segregation feeding system for sintering

In order to utilize the spontaneous accumulation of heat (SAH) reasonably and obtain the high quality sinter with low energy consumption, a lower fuel consumption modeling based on raw materials of a certain steel works was built. An air-flow segregation feeding (ASF) experimental equipment was designed to simulate strand feeding process and calculate the lower fuel consumption quantity. Compared with baseline test, the ASF experimental equipment was adopted. The results of sinter pot tests show that the solid fuel consumption is lower than that in baseline test, which is decreased by 5.8%. Meanwhile, other sinter indexes, such as pan yeild, tumbler strength and strand productivity are improved. The mineralogical examination indicates that the mineral compositions and micostructures are improved in sinter.

Evaluation indicators of Traditional Chinese Medicine syndromes for gouty arthritis with damp heat accumulation and the effect of administering Tongfeng Qingxiao formula(痛风清消方)

OBJECTIVE: To evaluate the indicators of an animal model of gouty arthritis(GA) with dampness heat accumulation and the intervention effect of Tongfeng Qingxiao formula(痛风清消方, TFQXF). METHODS: Seventy-two healthy adult Sprague-Dawley male rats were selected and randomly divided into a normal group, model group, low-dose group, mediumdose group, high-dose group, and diclofenac group using a random number table method, with 12 rats in each group. After group intervention, the general condition of the rats in each group was monitored and recorded, and the swelling index was measured. After separating the serum, the changes in glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase(AST), carbamide(UREA), creatinine(CREA), triglyceride(TG), total serum cholesterol(TC), low density lipoprotein cholesterol(LDL-C), and high density lipoprotein cholesterol(HDL-C) in the serum of the rats in each group were measured using an automatic biochemical analyzer. The levels of motilin(MTL), gastrin(GAS), endothelin(ET), calcitonin gene-related peptide(CGRP), heat shock protein 70(HSP70), interleukin(IL)-1β, and nuclear factor kappa-B(NF-κB) in the serum of the rats in each group were evaluated using enzyme-linked immunosorbent assay(ELISA) kits. Kidney tissues were used to evaluate the protein and m RNA expression of aquaporin(AQP) 1 and AQP2. Colon tissue was used to evaluate the protein and m RNA expression of AQP3 and AQP4 by Western blotting(WB) assay and real-time quantitative polymerase chain reaction(RT-q PCR). The levels of ALT, AST, UREA, and CREA were used to evaluate the liver and kidney function of rats. The levels of MTL and GAS were used to evaluate the gastrointestinal function of rats. The levels of TG, TC, LDL-C, HDL-C, AQP1, AQP2, AQP3, and AQP4 were used to evaluate the "dampness" syndrome performance in rats. The levels of ET, CGRP, and HSP70 were used to evaluate the "heat" syndrome performance in rats. The levels of IL-1β and NF-κB were used to evaluate the degree of inflammation in rats. The pathological changes in synovial and colonic tissues were observed by hematoxylin and eosin staining. RESULTS: Except for the normal group, after modeling treatment, the ankle joint of rats in both the model group and drug treatment groups gradually swelled, reaching a peak at 12 h, and then gradually began to subside. The results of biochemical analyzer detection indicated that the serum ALT, AST, UREA, CREA, TG, TC and LDL-C levels were significantly higher, but the HDL-C level was significantly lower in the rats of the model group than in the rats of the normal group(P < 0.05). The serum ALT, AST, UREA, CREA, MTL, TC and LDL-C levels were significantly lower, but the HDL-C level was significantly higher in the rats of all drug treatment groups than in the rats of the model group(P < 0.05). The results of ELISA detection indicated that the MTL, GAS, ET, HSP70, IL-1β,and NF-κB levels were significantly higher, but the CGRP level was significantly lower in the rats of the model group than in the rats of the normal group(P < 0.05). The levels of MTL, GAS, ET, HSP70, IL-1β, and NF-κB were significantly lower, but CGRP was significantly higher in the rats of the drug treatment groups than in the rats of the model group(P < 0.05). The results of WB and RTq PCR indicated that compared to the normal group, the levels of AQP1 and AQP2 in the model group were significantly higher in the kidney tissue, whereas the levels of AQP3 and AQP4 were significantly lower in the colon tissue(P < 0.05). Compared to those in the model group, the levels of AQP1 and AQP2 in the drug treatment groups were significantly lower in the kidney tissue, whereas the levels of AQP3 and AQP4 were significantly higher in the colon tissue(P < 0.05). In the model group, erosion of the colonic mucosal surface and inflammatory exudate occurred. Some mucosal epithelium had fallen off, the number of glands in the lamina propria was lower, many inflammatory cells infiltrated the interstitial layer, the connective tissue in the submucosa became loose and edematous, and lymph follicles developed. We found a significant proliferation of synovial cells in the ankle joint, an increase in cell density and neovascularization, and visible infiltration of inflammatory cells. The cartilage surface was not smooth. However, each drug group could improve the pathological changes in intestinal and synovial tissues to varying degrees. CONCLUSIONS: Blood lipid metabolism indexes and AQPs could be used as objective evaluation indexes for the "dampness" syndrome performance of damp-heat accumulation type GA. ET, HSP70 and CGRP could be used as objective evaluation indexes for the "heat" syndrome performance, and the immune inflammation index could be used as objective evaluation indexes for the inflammation degree. The overall efficacy of TFQXF in the treatment of damp-heat accumulation-type GA could be determined by adjusting the above objective evaluation indexes. It provided some ideas and directions for clinical risk assessments and drug development of GA.

Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data

The accumulation of thermal time usually represents the local heat resources to drive crop growth.Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity.To solve the critical problems of estimating air temperature(T a) and filling in missing pixels due to cloudy and low-quality images in growing degree days(GDDs) calculation from remotely sensed data,a novel spatio-temporal algorithm for T a estimation from Terra and Aqua moderate resolution imaging spectroradiometer(MODIS) data was proposed.This is a preliminary study to calculate heat accumulation,expressed in accumulative growing degree days(AGDDs) above 10 ℃,from reconstructed T a based on MODIS land surface temperature(LST) data.The verification results of maximum T a,minimum T a,GDD,and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels.Overall,MODIS-derived AGDD was slightly underestimated with almost 10% relative error.However,the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper.Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring,agricultural climatic regionalization,and agro-meteorological disaster detection at the regional scale.

Super-high bed sintering for iron ores: inhomogeneous phenomena and its mechanism during mineralizing

The inhomogeneous sinter properties in super-high bed sintering have been reported in our previous research.To inves-tigate the reasons for the inhomogeneous phenomena,detailed sampling and analysis of mixed material bed and sintered bed in super-high bed sintering plant were executed.The results indicated that the higher porosity and thinner dendrite of silico-ferrite of calcium and aluminum in the upper layer as well as dense structure and higher secondary hematite content in the lower layer led to the heterogeneities of mechanical strength and reduction properties exceeding 20%and 10%,respectively.From the bed top downward,the basicity of mixed material decreased from 2.13 to 1.68 because the average particle size increased from 2.65 to 4.56 mm.Fluxes and fuels gathered in finer particles(-3 mm)of mixed material,and the-3 mm particles of mixed material generated more liquid phase than+3 mm ones.The heat input of super-high sintering bed was inhomogeneous due to the heat accumulation effect and unreasonable fuel distribution.The inhomo-geneous sintering heat condition in sintering bed resulted in the different quantities and properties of liquid phase.The inhomogeneous quantities and properties of liquid phase that were influenced by inhomogeneous distribution of chemical composition,particle size,and heat input led to inhomogeneous mineralizing results.Homogeneous mineralizing condition is the key for homogeneous super-high bed sintering.

Thermal Inertia of 330 MW Circulating Fluidized Bed Boiler during Load Change

The operating principles of Circulating Fluidized Bed(CFB)boilers involve a significant amount of heat accumulation,which forms the thermal inertia of the boiler and hinders the improvement of its variable load response rate.This study aims to characterize the thermal inertia of CFB boilers by evaluating the change in the boiler's heat accumulation corresponding to the change in unit power generation.The thermal inertia of a 330MW CFB boiler was determined through the collection of operating data under four different operating conditions of 30%,50%,75%,and 100%load.The study proposes to substitute the existing refractory material with a metal grille to reduce the thermal inertia of the boiler.The effect of the metal grille on heat transfer was confirmed through verification on a 440 t/h CFB boiler,and its performance change and thermal inertia reduction were further predicted.The results indicate that over 50%of the total thermal inertia of CFB boilers originates from the refractory material.The use of metal grille in place of refractory material improved heat transfer in the furnace,resulting in a decrease of the furnace chamber temperature by 13℃in the 330 MW CFB boiler.This reduction of thermal inertia by 30%-35%will facilitate faster load lifting and lowering of the boiler,fulfilling the requirement for flexible peaking.