本文以數值法模擬具水平隔板正方形空間內低溫水自然對流熱傳，方形空間的兩鉛直壁維持不同之等溫，另兩水平壁假設絕熱邊界條件。主要探討密度分布參數R、瑞利數 Ra與無因次分隔板長度L/W對等流線、等溫線與熱傳之影響，而無因次分隔板高度H/W設為定值0.5。數值解顯示：當R=0.5且Ra=104時，裝上L/W =0.75的隔板可增加99%熱傳率；但，當R=0.4且Ra=104時，裝上L/W =0.25的隔板反而減少10.8%熱傳率。

This study reports numerical results on the natural convection heat transfer of water near its density maximum in a square cavity with a partition on the hot wall. The two vertical walls of the cavity are respectively heated and cooled, while the two horizontal walls are adiabatic. Analytical descriptions of flow patterns, temperature profiles in the water layer and convective heat-transfer coefficients are presented in this study for various density distribution parameters R, Rayleigh number Ra, and dimensionless length of the partition L/W. The dimensionless height of the partition H/W is set to be 0.5. Numerical results indicate that adding partition on the hot wall can increase the rate of heat transfer by as much as 99% compared with a wall without partition for R=0.5, Ra=104 and L/W =0.75. But for R=0.4, Ra=104 and L/W =0.25, the decrease in heat transfer is 10.8%.