Shaojun Xia

Optimal paths for minimizing entropy generation during heat transfer processes with a generalized heat transfer law

An investigation of finite-time heat transfer processes between high- and low-temperature sides with a generalized heat transfer law (q∝[Δ(Tn)]m) is presented in this paper. Optimal heating and cooling strategies for minimizing entropy generation are derived for the fixed initial and final temperatures of the low-temperature side working fluid. Optimal paths are compared with the common strategies of constant heat flux and constant source temperature operation by numerical examples. The condition corresponding to the minimum entropy generation strategy is not only valid for Newton’s [q∝(ΔT)] and linear phenomenological [q∝Δ(T−1)] heat transfer laws but also valid for heat transfer law (q∝[Δ(T−1)]m). The obtained results are general and can provide some theoretical guidelines for the designs and operations of practical heat exchangers.

Optimal paths for minimizing lost available work during heat transfer processes with a generalized heat transfer law

A common of finite-time heat transfer processes between high- and low-temperature sides with a generalized heat transfer law [q ∝ (Δ(Tn ))m] are studied in this paper. The optimal heating and cooling configurations for minimizing lost available work are derived for the fixed initial and final temperatures of the working fluid of the system (low-temperature side). Optimal paths are compared with the common strategies of constant heat flux, constant source (reservoir) temperature and the minimum entropy generation operation by numerical examples. The condition corresponding to the minimum lost available work strategy is that corresponding to a constant rate of lost available work, not only valid for Newtons heat transfer law [q ∝ ΔT] but also valid for the generalized convective heat transfer law [q ∝ (ΔT)m ]. The obtained results are more general and can provide some theoretical guidelines for the designs and operations of practical heat exchangers.

Optimal Concentration Configuration of Consecutive Chemical Reaction A ⇔ B ⇔ C for Minimum Entropy Generation

Abstract A consecutive chemical reaction A⇔B⇔C

Optimizing piston velocity profile for maximum work output from a generalized radiative law Diesel engine

A \Leftrightarrow B \Leftrightarrow C

Finite time exergy with generalised heat transfer law

is studied in this paper. The optimal concentration configuration of the reaction for minimum entropy generation with fixed yield of aimed product B

Dynamic performance limits for a class of multistage chemical power consumption system

B