发动机进气测量层流流量计的研制

介绍了自行开发的用于发动机进气测量的层流流量计,该流量计基于气体在层流段流量与压差成正比的原理设计。实际应用表明,该流量计较好地解决了发动机进气流量测量中存在的进气脉动大、测量范围广等问题,具有测量精度高,量程比大,阻力小等优点,可用于发动机进气测量及性能标定。     

节流流量计测量脉动流的研究

一、节流流量计测量脉动流存在的问题节流流量计是工业上应用最广泛的流量计，它具有结构简单、可靠性高等优点。节流流量计是利用节流装置前后的差压与平均流速的关系，根据测量的差压值计算出流量的，差压△Ｐ和流量Ｑ之间存在着Ｑ＝Ｋ△Ｐ的平方关系。所以只要测量出节...     

漏气自动测量系统

<正> 本文叙述的漏气自动测量系统使用的是热式流量计,它是气体质量流量测定装置中的一种。热式流量计根据随流体移动的热量和质量流量之间的关系测定流量,在原来的机能上增加质量流量测定,具有低压损、小流量、易于测量漏气量等特点。另一方面,当传感器粘附着水和油时,从原理上讲不能进行正确的测量,因此,该测量系统除了有流量计之外,是由除去附着的水和油等液体的装置,以及补偿除液装置产生压力损失的补偿装置构成。     

毕托巴流量计在非满管流量测量中的应用

针对传统的堰、槽式流量计不能满足石化行业现实生产测量的现状,探索使用毕托巴流量计在非满管流量中进行测量,取得了一定的成效。     

斯派莎克推出专用于饱和蒸汽计量的TVA流量计

全新推出的TVA流量计是斯派莎克流量计家族中的一员。其特殊设计专门用于饱和蒸汽的流量测量。TVA流量计是当工艺负荷变化较大时用于饱和蒸汽流量计量的理想设备,主要特点包括：     

热线式空气流量计的研究

热线式空气流量计是测量空气质量流量的一种重要工具。本文设计了一种广泛应用于电控发动机的热线式空气流量计。介绍了热线式空气流量计的理论依据、基本原理、设计和使用方面的问题 ,还对恒温反馈控制和温度补偿作了说明。在电控喷射发动机的汽车上作进气流量检测时 ,不用对进气压力和温度的变化作修正 ,因为它直接测得的是质量流量 ,在用作通用流量计时 ,应对测量区作线性化处理。     

涡街流量计测量系统不确定度的分析

通过分析涡街流量计在液体和气体流量测量应用中的工作原理,讨论了涡街流量计测量系统中仪器尺寸精度、斯特劳哈尔数、涡旋频率测量、温/压测量以及其它环节的系统不确定度分量和不确定度的合成。通过对测量系统不确定度的分析,提出了涡街流量计测量系统的改进方向以及涡街流量计的干标定问题,促进节能减排工作的进展。     

能源计量中蒸汽表的选型

在氯碱化工生产企业中 ,合理地选择蒸汽流量计表型 ,正确地安装 ;准确地设定运行参数是搞好蒸汽流量计量的关键。化学厂采用涡街流量传感器测量蒸汽流量 ,经过几年的运行 ,效果较好     

应用MST—P超声流量计准确测量管内不同流态的液体流量

根据超声波流量计的测量原理，通过分析管内液体不同流速分布对流量测量结果的影响，并结合现场测量试验数据，提出了一套用ＭＳＴ－Ｐ流量计准确测算管内液体流量的方法。     

科利奥利质量流量变送器

一、引言早在60年代初期,为了有别于把体积式流量计通过换算或补偿而得到质量的流量计,C.M.HALSELL曾给质量流量计下过一个定义:一种流量测量装置,其敏感元件的反应比例于真正的质量流量. 所谓“真正的质量流量”,是指流量计的输出信号应与流体的物理性质如温度、压力、密度、粘度、电导等无关,并且与湿度、大气压、温度等环境条件也无关. 四十年代,科学家和工程师们就开始开发质量流量计,借以消除容积测量的误差及     

格栅密度对汽车热式空气流量计性能影响的试验研究

构建了汽车热式空气流量计性能检测试验平台,对国产某型热式空气流量计进行了试验研究,分析了格栅密度变化对空气流量计精度的影响规律。试验结果表明,格栅密度是影响空气流量及精度的一个关键结构参数。随着格栅密度的减少,在无干扰情况下,空气进入流量计中比较流畅,误差精度比较高,但抗干扰能力急剧下降。在同一转速旋转干扰源状态下,格栅密度越小,误差就越大,很难实现符合标准误差的要求。     

Thermal performance of three solar air heaters

This paper reports the thermal analysis and the results of thermal performance tests of solar air heaters with V-corrugated absorber plates. Six collector units were used to test three collector types: (a) flow over the absorber, (b) flow on both sides of the absorber, and (c) flow under the absorber. Paired simultaneous testing was used for collectors of the same type to check thermal performance differences which might occur due to construction differences or testing variables. Predictions of collector thermal performance, when using temperatures and environmental data from the tests, were in good agreement with the corresponding measured thermal performance. The predicted performance, particularly with solar glass, indicated very good thermal efficiency for vee corrugated absorber plates.     

炉灶一体式民用生物质炊事炉的设计与性能测试

针对目前炉灶分离式民用生物质炊事炉存在热效率低、燃气输送管路复杂、焦油堵塞管路及污染环境等缺点,基于生物质热解气化原理,设计了一种炉灶一体式生物质炊事炉,并对该炉的气化性能和燃烧性能进行了测试.试验结果表明:一次供风流量的变化对H2和CO的影响较明显,当空气流量为0.80 m3/min时,气化效率可达63.6％,热值可达4 071.2 kJ/m3;灶头的二次风适宜流量为0.030 m3/min,可使该炉的热效率达36.3％,炊事火力强度达4.79 kW.     

无盖板渗透型集热器热性能的对比试验

利用太阳能空气加热系统实验台,对黑、深绿和深蓝3种颜色无盖板渗透型集热器的热性能进行了户外瞬态对比试验。试验结果表明:太阳辐射照度和风量是影响系统热性能的重要因素。在高档和低档两种风量下,黑色集热器的瞬时平均热效率分别为76.04%和67.50%,高于普通平板太阳能空气集热器;集热器表面颜色对其热性能有一定影响,在高档和低档两种风量下,深绿色和深蓝色集热器的瞬时平均热效率比黑色集热器低15%～22%,空气温升低3～4℃,但仍然优于普通平板空气集热器。从保持建筑立面美观考虑,无盖板渗透型集热器的集热板可以采用颜色较深的彩色,不会对系统热性能造成较大影响。     

The recycle-effect on cool–thermal discharge systems under melt removal and flow rate variations

A mathematical model to simulate the production of chilled air during on-peak power consumption hours in cool–thermal discharge systems with external recycle under melt removal and varied flow rate of flowing air has been developed theoretically. Equations have been derived for estimating the controlling air flow rate when the outlet chilled air temperature is specified. Three cases of inlet ambient temperatures of flowing air were illustrated to study the influence of recycle ratio on the performance improvement of cool–thermal discharge systems, the volumetric flow rate variations and Nusselt number increment due to a larger convective heat transfer rate were also delineated.     

Dimensional analysis of performance of a solar-cum-wind aspirator developed at ciae

Air flow through a solar-cum-wind aspirator is induced by both thermal buoyancy and wind effects. A similitude study has been conducted to characterize air flow rates through solar-cum-wind aspirators. A relationship between the air flow rate and height and diameter of the aspirator, wind speed, temperature rise inside the stack, and relevant air properties has been developed on the basis of the experimental data collected under field conditions.     

Thermal performance of an air solar collector with an absorber plate made of recyclable aluminum cans

The present paper describes the development and testing of an efficient single-glass air solar collector with an absorber plate made of recyclable aluminum cans (RAC). This collector was designed as a proposal to use recycle recyclable materials to build absorber plates of air solar collectors at an acceptable cost. The absorber plate of the collector consisted of eight circular cross section air flow channels of 128 recyclable aluminium cans. Each channel was built with 16 recyclable cans blackened with common opaque black paint of 0.903 absorptance and 0.097 reflectance. The design parameters to determine the size of the collector were obtained by implementing a simulation model for double flow air solar collectors. Also, to determine the appropriate configuration for a uniform air flow distribution inside the eight RAC air channels, a hydrodynamic numerical study was carried out. The RAC air solar collector designed and built was tested outdoors following the ASHRAE 93-86 standard to determine the time constant, the thermal efficiency and the incidence angle modifier. Comparison between the predicted theoretical temperatures and the measured ones were in good agreement. Comparison between the thermal efficiency of the RAC air solar collector with the ones reported in the literature is presented.     

Testing method for thermal performance based rating of various solar dryer designs

A generalized methodology is developed for thermal testing of various solar dryer designs operated for natural and forced air flow conditions. The steady state mathematical model based on heat balance concept of solar dryer without load is applied to identify the dimensionless parameter called no-load performance index (NLPI). Laboratory models of direct (cabinet), indirect and mixed mode solar dryer are designed and constructed to perform steady state thermal tests for natural and forced air circulation. The dryers with no-load are operated with air passage between absorber plate and glass cover for the range of 300–800 W/m² and 0.009–0.026 kg/s of absorbed thermal energy and air mass flow rate respectively under indoor simulation conditions. The present study reveals that the forced convection operated dryer provides higher NLPI in contrast to that of natural convection. The comparative performance analysis of dryers indicates that the mixed mode dryer exhibits maximum value of NLPI followed by indirect and cabinet ones for both natural and forced air circulation. It is also found that for any dryer operating at given air flow condition, almost invariable NLPI values have been obtained for a wide range of absorbed energy and ambient air temperature data, thus facilitating performance comparison between different dryer designs on equitable basis. The results of statistical analysis showing low standard errors of mean further demonstrate good consistency in NLPI values for various dryer designs. The uncertainty in NLPI due to error in measurement of several parameters by instruments ranges from 0.79 to 1.96% for various dryer designs operated under different conditions.     

Effect of air flow rate distribution and flowing direction on the thermal stress of a solid oxide fuel cell stack with cross-flow configuration

This study investigates the effect of non-uniform distribution of the air inlet flow rate and change of air flowing direction on the thermal stress of a solid oxide fuel cell stack with cross-flow configuration. This study considers three patterns of air inlet flow rate in the transverse direction of each stack, and five patterns of air inlet flow rate in the stacking direction. The software package for simulation is reliable through an accuracy comparison, and it analyzes the current density, temperature, and thermal stress distribution of a SOFC stack with 20 layers. The results show that the progressively increasing profile of the air inlet flow rate along the x direction drops the cell thermal stress of a SOFC unit. Moreover, the non-uniform profile of air inlet flow rate in the stacking direction affects the position of the region with high thermal stress of the SOFC stack, and changing flow direction of the air obviously drops down the thermal stress without affecting the power generation of the SOFC stack.     

An analytical model to predict the thermal performance of a novel parallel flow packed bed solar air heater

A design of a parallel flow solar air heater with packed material in its upper channel and capable of providing a higher heat flux compared to the conventional non-porous bed double flow systems is presented. An analytical model describing the various temperatures and heat transfer characteristics of such a parallel flow packed bed solar air heater (PFPBSAH) has been developed and employed to study the effects of the mass flow rate and varying porosities of the packed material on its thermal performance. The model employs an iterative solution procedure to solve the governing energy balance equations describing the complex heat and mass exchanges involved. To validate the proposed analytical model, comparisons between theoretical and experimental results showed that good agreement is achieved with reasonable accuracy. Also, PFPBSAH is found to perform more efficiently than the conventional non-porous double flow solar air heaters with 10–20% increase in its thermal efficiency. Furthermore, the effect of the fraction of mass flow rate in the upper or lower flow channel of PFPBSAH device on its performance, has also investigated theoretically. The fraction of the mass flow rate in the respective channels of the PFPBSAH is shown to be dominant parameter in determining the effective thermal efficiency of the heater.