Debt mutual funds primarily invest in long-term and short-term fixed income securities like government bonds, corporate debentures, money market instrument, etc. When market fluctuate debt instruments give a specific income at regular interval and thus your short-term corpus is not much affected.
You can choose short-term Debt funds marketed by banks like Axis, HDFC, etc, or Blue chip like L&T, Birla, etc.
Please note that it is just a views and you should act only after you have done your research or after consulting a financial advisor.