工质线性变比热对内可逆Rallis循环功率效率性能的影响  

Effect of linear variable specific heat of working medium on power efficiency performance of endoreversible Rallis cycle

作　　者：席雪涛 戈延林 陈林根 张继文 冯辉君 XI Xue-tao;GE Yan-lin;CHEN Lin-gen;ZHANG Ji-wen;FENG Hui-jun

机构地区：[1]武汉工程大学热科学与动力工程研究所,湖北武汉430205 [2]湖北省绿色化工装备工程技术研究中心,湖北武汉430205 [3]武汉工程大学机电工程学院,湖北武汉430205

出　　处：《节能》2024年第5期47-51,共5页Energy Conservation

基　　金：国家自然科学基金(项目编号:52171317、51779262);武汉工程大学研究生教育创新基金项目(项目编号:CX2022073)。

摘　　要：应用有限时间热力学理论建立工质比热随温度线性变化时内可逆Rallis循环模型,导出循环的功率(P)和效率(η)的解析式。通过数值算例分析循环增压比(λ)、压缩比(ε)、预胀比(ρ)、传热损失(B)和工质比热随温度线性变化系数(k_(1))对P与膨胀比(σ)、η与σ以及P与η特性曲线的影响。结果显示:循环P-σ和η-σ特性曲线为类抛物线型,循环P-η特性曲线为扭叶型;存在最佳的膨胀比σ_(P)和σ_(η),分别使P和η达到最大值(P_(max)和η_(max));随着ε和λ的增大,P_(max)、σ_(P)、η_(max)、σ_(η)、η_(max)对应的功率(P_(η))和P_(max)对应的效率(η_(P))单调递增;随着ρ的增大,P_(max)、η_(max)、σ_(η)和P_(η)单调递增,σ_(P)不变,η_(P)单调递减;随着B和k1的增大,η_(max)和η_(P)单调递减,σ_(η)和P_(η)单调递增。将所得结论与恒比热内可逆Rallis循环的结论进行对比,结果显示:随ρ的增大,σ_(P)不变,恒比热时σ_(P)单调递增;η_(P)单调递减,恒比热时η_(P)单调递增。通过分析可知工质比热变化对Rallis循环性能的影响较为明显,所得结论对该循环的应用有一定参考意义。An endoreversible Rallis cycle model is established by finite-time thermodynamic theory when the specific heat of working medium varies linearly with temperature.The analytical expressions of power(P)and efficiency(η)of the cycle are derived.The effects of cyclic pressurization ratio(λ),compression ratio(ε),pre-expansion ratio(ρ),heat transfer loss(B)and the coefficient of linear variation of specific heat with temperature(k_(1))on the characteristic curves of P and expansion ratio(σ),ηandσand,P andηare analyzed by numerical examples.The results show that the cyclic P-σandη-σcharacteristic curves are parabola-like,and the cyclic P-ηcharacteristic curves are twisted blade shapes.There are optimum expansion ratiosσ_(P) andσ_(η),which make P andηreach the maximum(P_(max) and η_(max)),respectively.With the increase ofεandλ,the power(P_(η))corresponding to P_(max),σ_(P),η_(max),σ_(η),η_(max) and the efficiency(η_(P))corresponding to P_(max) increase monotonously.With the increase ofρ,P_(max),η_(max),σ_(η)and P_(η)increase monotonously,whileσ_(P) remains unchanged andη_(P) decreases monotonically.With the increase of B and k_(1),η_(max) andη_(P) decrease monotonously,andσ_(η)and P_(η)increase monotonously.The results are compared with the results of endoreversible Rallis cycle with constant specific heat.The results show that with the increase ofρ,σ_(P) remains unchanged,while at constant specific heat,σ_(P) increases monotonously.η_(P) decreases monotonously and increases monotonously at constant specific heat.Through the analysis,it can be seen that the change of specific heat of working medium has an obvious influence on the performance of Rallis cycle,and the conclusions obtained have certain reference significance for the application of this cycle.

关 键 词：有限时间热力学 内可逆Rallis循环 工质变比热 性能优化 

分 类 号：TK123[动力工程及工程热物理—工程热物理]